Kill the_index part2, header file cleanup

index dc4a019057..025dfed7ab 100644
@@ -110,14 +110,14 @@ struct apply_state {
 	int applied_after_fixing_ws;
 };
 
-extern int apply_parse_options(int argc, const char **argv,
-			       struct apply_state *state,
-			       int *force_apply, int *options,
-			       const char * const *apply_usage);
-extern int init_apply_state(struct apply_state *state,
-			    const char *prefix);
-extern void clear_apply_state(struct apply_state *state);
-extern int check_apply_state(struct apply_state *state, int force_apply);
+int apply_parse_options(int argc, const char **argv,
+			struct apply_state *state,
+			int *force_apply, int *options,
+			const char * const *apply_usage);
+int init_apply_state(struct apply_state *state,
+		     const char *prefix);
+void clear_apply_state(struct apply_state *state);
+int check_apply_state(struct apply_state *state, int force_apply);
 
 /*
  * Some aspects of the apply behavior are controlled by the following

@@ -126,9 +126,8 @@ extern int check_apply_state(struct apply_state *state, int force_apply);
 #define APPLY_OPT_INACCURATE_EOF	(1<<0) /* accept inaccurate eof */
 #define APPLY_OPT_RECOUNT		(1<<1) /* accept inaccurate line count */
 
-extern int apply_all_patches(struct apply_state *state,
-			     int argc,
-			     const char **argv,
-			     int options);
+int apply_all_patches(struct apply_state *state,
+		      int argc, const char **argv,
+		      int options);
 
 #endif

index 442d464db6..46340010bb 100644
@@ -42,31 +42,31 @@ struct attr_check {
 	struct attr_stack *stack;
 };
 
-extern struct attr_check *attr_check_alloc(void);
-extern struct attr_check *attr_check_initl(const char *, ...);
-extern struct attr_check *attr_check_dup(const struct attr_check *check);
+struct attr_check *attr_check_alloc(void);
+struct attr_check *attr_check_initl(const char *, ...);
+struct attr_check *attr_check_dup(const struct attr_check *check);
 
-extern struct attr_check_item *attr_check_append(struct attr_check *check,
-						 const struct git_attr *attr);
+struct attr_check_item *attr_check_append(struct attr_check *check,
+					  const struct git_attr *attr);
 
-extern void attr_check_reset(struct attr_check *check);
-extern void attr_check_clear(struct attr_check *check);
-extern void attr_check_free(struct attr_check *check);
+void attr_check_reset(struct attr_check *check);
+void attr_check_clear(struct attr_check *check);
+void attr_check_free(struct attr_check *check);
 
 /*
  * Return the name of the attribute represented by the argument.  The
  * return value is a pointer to a null-delimited string that is part
  * of the internal data structure; it should not be modified or freed.
  */
-extern const char *git_attr_name(const struct git_attr *);
+const char *git_attr_name(const struct git_attr *);
 
-extern int git_check_attr(const char *path, struct attr_check *check);
+int git_check_attr(const char *path, struct attr_check *check);
 
 /*
  * Retrieve all attributes that apply to the specified path.
  * check holds the attributes and their values.
  */
-extern void git_all_attrs(const char *path, struct attr_check *check);
+void git_all_attrs(const char *path, struct attr_check *check);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,

@@ -76,6 +76,6 @@ enum git_attr_direction {
 void git_attr_set_direction(enum git_attr_direction new_direction,
 			    struct index_state *istate);
 
-extern void attr_start(void);
+void attr_start(void);
 
 #endif /* ATTR_H */

index a6c915c277..8c1e14980d 100644
@@ -159,17 +159,21 @@ static inline struct blame_origin *blame_origin_incref(struct blame_origin *o)
 		o->refcnt++;
 	return o;
 }
-extern void blame_origin_decref(struct blame_origin *o);
-
-extern void blame_coalesce(struct blame_scoreboard *sb);
-extern void blame_sort_final(struct blame_scoreboard *sb);
-extern unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e);
-extern void assign_blame(struct blame_scoreboard *sb, int opt);
-extern const char *blame_nth_line(struct blame_scoreboard *sb, long lno);
-
-extern void init_scoreboard(struct blame_scoreboard *sb);
-extern void setup_scoreboard(struct blame_scoreboard *sb, const char *path, struct blame_origin **orig);
-
-extern struct blame_entry *blame_entry_prepend(struct blame_entry *head, long start, long end, struct blame_origin *o);
+void blame_origin_decref(struct blame_origin *o);
+
+void blame_coalesce(struct blame_scoreboard *sb);
+void blame_sort_final(struct blame_scoreboard *sb);
+unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e);
+void assign_blame(struct blame_scoreboard *sb, int opt);
+const char *blame_nth_line(struct blame_scoreboard *sb, long lno);
+
+void init_scoreboard(struct blame_scoreboard *sb);
+void setup_scoreboard(struct blame_scoreboard *sb,
+		      const char *path,
+		      struct blame_origin **orig);
+
+struct blame_entry *blame_entry_prepend(struct blame_entry *head,
+					long start, long end,
+					struct blame_origin *o);
 
 #endif /* BLAME_H */

index cfd5328cc9..9799e894f7 100644
@@ -51,6 +51,6 @@ int write_index_as_tree(struct object_id *oid, struct index_state *index_state,
 int write_cache_as_tree(struct object_id *oid, int flags, const char *prefix);
 void prime_cache_tree(struct index_state *, struct tree *);
 
-extern int cache_tree_matches_traversal(struct cache_tree *, struct name_entry *ent, struct traverse_info *info);
+int cache_tree_matches_traversal(struct cache_tree *, struct name_entry *ent, struct traverse_info *info);
 
 #endif

index 01385d9288..0a0fa15b58 100644
@@ -57,35 +57,36 @@ struct delayed_checkout {
 
 extern enum eol core_eol;
 extern char *check_roundtrip_encoding;
-extern const char *get_cached_convert_stats_ascii(const struct index_state *istate,
-						  const char *path);
-extern const char *get_wt_convert_stats_ascii(const char *path);
-extern const char *get_convert_attr_ascii(const char *path);
+const char *get_cached_convert_stats_ascii(const struct index_state *istate,
+					   const char *path);
+const char *get_wt_convert_stats_ascii(const char *path);
+const char *get_convert_attr_ascii(const char *path);
 
 /* returns 1 if *dst was used */
-extern int convert_to_git(const struct index_state *istate,
-			  const char *path, const char *src, size_t len,
-			  struct strbuf *dst, int conv_flags);
-extern int convert_to_working_tree(const char *path, const char *src,
-				   size_t len, struct strbuf *dst);
-extern int async_convert_to_working_tree(const char *path, const char *src,
-					 size_t len, struct strbuf *dst,
-					 void *dco);
-extern int async_query_available_blobs(const char *cmd, struct string_list *available_paths);
-extern int renormalize_buffer(const struct index_state *istate,
-			      const char *path, const char *src, size_t len,
-			      struct strbuf *dst);
+int convert_to_git(const struct index_state *istate,
+		   const char *path, const char *src, size_t len,
+		   struct strbuf *dst, int conv_flags);
+int convert_to_working_tree(const char *path, const char *src,
+			    size_t len, struct strbuf *dst);
+int async_convert_to_working_tree(const char *path, const char *src,
+				  size_t len, struct strbuf *dst,
+				  void *dco);
+int async_query_available_blobs(const char *cmd,
+				struct string_list *available_paths);
+int renormalize_buffer(const struct index_state *istate,
+		       const char *path, const char *src, size_t len,
+		       struct strbuf *dst);
 static inline int would_convert_to_git(const struct index_state *istate,
 				       const char *path)
 {
 	return convert_to_git(istate, path, NULL, 0, NULL, 0);
 }
 /* Precondition: would_convert_to_git_filter_fd(path) == true */
-extern void convert_to_git_filter_fd(const struct index_state *istate,
-				     const char *path, int fd,
-				     struct strbuf *dst,
-				     int conv_flags);
-extern int would_convert_to_git_filter_fd(const char *path);
+void convert_to_git_filter_fd(const struct index_state *istate,
+			      const char *path, int fd,
+			      struct strbuf *dst,
+			      int conv_flags);
+int would_convert_to_git_filter_fd(const char *path);
 
 /*****************************************************************
  *

@@ -95,9 +96,10 @@ extern int would_convert_to_git_filter_fd(const char *path);
 
 struct stream_filter; /* opaque */
 
-extern struct stream_filter *get_stream_filter(const char *path, const struct object_id *);
-extern void free_stream_filter(struct stream_filter *);
-extern int is_null_stream_filter(struct stream_filter *);
+struct stream_filter *get_stream_filter(const char *path,
+					const struct object_id *);
+void free_stream_filter(struct stream_filter *);
+int is_null_stream_filter(struct stream_filter *);
 
 /*
  * Use as much input up to *isize_p and fill output up to *osize_p;

@@ -111,8 +113,8 @@ extern int is_null_stream_filter(struct stream_filter *);
  * such filters know there is no more input coming and it is time for
  * them to produce the remaining output based on the buffered input.
  */
-extern int stream_filter(struct stream_filter *,
-			 const char *input, size_t *isize_p,
-			 char *output, size_t *osize_p);
+int stream_filter(struct stream_filter *,
+		  const char *input, size_t *isize_p,
+		  char *output, size_t *osize_p);
 
 #endif /* CONVERT_H */

index a30da161da..81281a398b 100644
@@ -50,17 +50,17 @@ struct diff_filespec {
 	struct userdiff_driver *driver;
 };
 
-extern struct diff_filespec *alloc_filespec(const char *);
-extern void free_filespec(struct diff_filespec *);
-extern void fill_filespec(struct diff_filespec *, const struct object_id *,
-			  int, unsigned short);
+struct diff_filespec *alloc_filespec(const char *);
+void free_filespec(struct diff_filespec *);
+void fill_filespec(struct diff_filespec *, const struct object_id *,
+		   int, unsigned short);
 
 #define CHECK_SIZE_ONLY 1
 #define CHECK_BINARY    2
-extern int diff_populate_filespec(struct diff_filespec *, unsigned int);
-extern void diff_free_filespec_data(struct diff_filespec *);
-extern void diff_free_filespec_blob(struct diff_filespec *);
-extern int diff_filespec_is_binary(struct diff_filespec *);
+int diff_populate_filespec(struct diff_filespec *, unsigned int);
+void diff_free_filespec_data(struct diff_filespec *);
+void diff_free_filespec_blob(struct diff_filespec *);
+int diff_filespec_is_binary(struct diff_filespec *);
 
 struct diff_filepair {
 	struct diff_filespec *one;

@@ -86,9 +86,9 @@ struct diff_filepair {
 
 #define DIFF_PAIR_MODE_CHANGED(p) ((p)->one->mode != (p)->two->mode)
 
-extern void diff_free_filepair(struct diff_filepair *);
+void diff_free_filepair(struct diff_filepair *);
 
-extern int diff_unmodified_pair(struct diff_filepair *);
+int diff_unmodified_pair(struct diff_filepair *);
 
 struct diff_queue_struct {
 	struct diff_filepair **queue;

@@ -102,16 +102,16 @@ struct diff_queue_struct {
 	} while (0)
 
 extern struct diff_queue_struct diff_queued_diff;
-extern struct diff_filepair *diff_queue(struct diff_queue_struct *,
-					struct diff_filespec *,
-					struct diff_filespec *);
-extern void diff_q(struct diff_queue_struct *, struct diff_filepair *);
+struct diff_filepair *diff_queue(struct diff_queue_struct *,
+				 struct diff_filespec *,
+				 struct diff_filespec *);
+void diff_q(struct diff_queue_struct *, struct diff_filepair *);
 
-extern void diffcore_break(int);
-extern void diffcore_rename(struct diff_options *);
-extern void diffcore_merge_broken(void);
-extern void diffcore_pickaxe(struct diff_options *);
-extern void diffcore_order(const char *orderfile);
+void diffcore_break(int);
+void diffcore_rename(struct diff_options *);
+void diffcore_merge_broken(void);
+void diffcore_pickaxe(struct diff_options *);
+void diffcore_order(const char *orderfile);
 
 /* low-level interface to diffcore_order */
 struct obj_order {

@@ -138,11 +138,11 @@ void diff_debug_queue(const char *, struct diff_queue_struct *);
 #define diff_debug_queue(a,b) do { /* nothing */ } while (0)
 #endif
 
-extern int diffcore_count_changes(struct diff_filespec *src,
-				  struct diff_filespec *dst,
-				  void **src_count_p,
-				  void **dst_count_p,
-				  unsigned long *src_copied,
-				  unsigned long *literal_added);
+int diffcore_count_changes(struct diff_filespec *src,
+			   struct diff_filespec *dst,
+			   void **src_count_p,
+			   void **dst_count_p,
+			   unsigned long *src_copied,
+			   unsigned long *literal_added);
 
 #endif

index dedac472ca..4a8885fb0f 100644
@@ -253,15 +253,15 @@ const char *diff_line_prefix(struct diff_options *);
 
 extern const char mime_boundary_leader[];
 
-extern struct combine_diff_path *diff_tree_paths(
+struct combine_diff_path *diff_tree_paths(
 	struct combine_diff_path *p, const struct object_id *oid,
 	const struct object_id **parents_oid, int nparent,
 	struct strbuf *base, struct diff_options *opt);
-extern int diff_tree_oid(const struct object_id *old_oid,
-			 const struct object_id *new_oid,
-			 const char *base, struct diff_options *opt);
-extern int diff_root_tree_oid(const struct object_id *new_oid, const char *base,
-			      struct diff_options *opt);
+int diff_tree_oid(const struct object_id *old_oid,
+		  const struct object_id *new_oid,
+		  const char *base, struct diff_options *opt);
+int diff_root_tree_oid(const struct object_id *new_oid, const char *base,
+		       struct diff_options *opt);
 
 struct combine_diff_path {
 	struct combine_diff_path *next;

@@ -278,33 +278,33 @@ struct combine_diff_path {
 	st_add4(sizeof(struct combine_diff_path), (l), 1, \
 		st_mult(sizeof(struct combine_diff_parent), (n)))
 
-extern void show_combined_diff(struct combine_diff_path *elem, int num_parent,
-			      int dense, struct rev_info *);
+void show_combined_diff(struct combine_diff_path *elem, int num_parent,
+			int dense, struct rev_info *);
 
-extern void diff_tree_combined(const struct object_id *oid, const struct oid_array *parents, int dense, struct rev_info *rev);
+void diff_tree_combined(const struct object_id *oid, const struct oid_array *parents, int dense, struct rev_info *rev);
 
-extern void diff_tree_combined_merge(const struct commit *commit, int dense, struct rev_info *rev);
+void diff_tree_combined_merge(const struct commit *commit, int dense, struct rev_info *rev);
 
 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b);
 
-extern int diff_can_quit_early(struct diff_options *);
+int diff_can_quit_early(struct diff_options *);
 
-extern void diff_addremove(struct diff_options *,
-			   int addremove,
-			   unsigned mode,
-			   const struct object_id *oid,
-			   int oid_valid,
-			   const char *fullpath, unsigned dirty_submodule);
+void diff_addremove(struct diff_options *,
+		    int addremove,
+		    unsigned mode,
+		    const struct object_id *oid,
+		    int oid_valid,
+		    const char *fullpath, unsigned dirty_submodule);
 
-extern void diff_change(struct diff_options *,
-			unsigned mode1, unsigned mode2,
-			const struct object_id *old_oid,
-			const struct object_id *new_oid,
-			int old_oid_valid, int new_oid_valid,
-			const char *fullpath,
-			unsigned dirty_submodule1, unsigned dirty_submodule2);
+void diff_change(struct diff_options *,
+		 unsigned mode1, unsigned mode2,
+		 const struct object_id *old_oid,
+		 const struct object_id *new_oid,
+		 int old_oid_valid, int new_oid_valid,
+		 const char *fullpath,
+		 unsigned dirty_submodule1, unsigned dirty_submodule2);
 
-extern struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
+struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
 
 #define DIFF_SETUP_REVERSE      	1
 #define DIFF_SETUP_USE_CACHE		2

@@ -314,17 +314,17 @@ extern struct diff_filepair *diff_unmerge(struct diff_options *, const char *pat
  * Poor man's alternative to parse-option, to allow both stuck form
  * (--option=value) and separate form (--option value).
  */
-extern int parse_long_opt(const char *opt, const char **argv,
-			 const char **optarg);
-
-extern int git_diff_basic_config(const char *var, const char *value, void *cb);
-extern int git_diff_heuristic_config(const char *var, const char *value, void *cb);
-extern void init_diff_ui_defaults(void);
-extern int git_diff_ui_config(const char *var, const char *value, void *cb);
-extern void diff_setup(struct diff_options *);
-extern int diff_opt_parse(struct diff_options *, const char **, int, const char *);
-extern void diff_setup_done(struct diff_options *);
-extern int git_config_rename(const char *var, const char *value);
+int parse_long_opt(const char *opt, const char **argv,
+		   const char **optarg);
+
+int git_diff_basic_config(const char *var, const char *value, void *cb);
+int git_diff_heuristic_config(const char *var, const char *value, void *cb);
+void init_diff_ui_defaults(void);
+int git_diff_ui_config(const char *var, const char *value, void *cb);
+void diff_setup(struct diff_options *);
+int diff_opt_parse(struct diff_options *, const char **, int, const char *);
+void diff_setup_done(struct diff_options *);
+int git_config_rename(const char *var, const char *value);
 
 #define DIFF_DETECT_RENAME	1
 #define DIFF_DETECT_COPY	2

@@ -342,8 +342,8 @@ extern int git_config_rename(const char *var, const char *value);
 
 #define DIFF_PICKAXE_IGNORE_CASE	32
 
-extern void diffcore_std(struct diff_options *);
-extern void diffcore_fix_diff_index(struct diff_options *);
+void diffcore_std(struct diff_options *);
+void diffcore_fix_diff_index(struct diff_options *);
 
 #define COMMON_DIFF_OPTIONS_HELP \
 "\ncommon diff options:\n" \

@@ -373,9 +373,9 @@ extern void diffcore_fix_diff_index(struct diff_options *);
 "                show all files diff when -S is used and hit is found.\n" \
 "  -a  --text    treat all files as text.\n"
 
-extern int diff_queue_is_empty(void);
-extern void diff_flush(struct diff_options*);
-extern void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc);
+int diff_queue_is_empty(void);
+void diff_flush(struct diff_options*);
+void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc);
 
 /* diff-raw status letters */
 #define DIFF_STATUS_ADDED		'A'

@@ -397,24 +397,24 @@ extern void diff_warn_rename_limit(const char *varname, int needed, int degraded
  * This is different from find_unique_abbrev() in that
  * it stuffs the result with dots for alignment.
  */
-extern const char *diff_aligned_abbrev(const struct object_id *sha1, int);
+const char *diff_aligned_abbrev(const struct object_id *sha1, int);
 
 /* do not report anything on removed paths */
 #define DIFF_SILENT_ON_REMOVED 01
 /* report racily-clean paths as modified */
 #define DIFF_RACY_IS_MODIFIED 02
-extern int run_diff_files(struct rev_info *revs, unsigned int option);
-extern int run_diff_index(struct rev_info *revs, int cached);
+int run_diff_files(struct rev_info *revs, unsigned int option);
+int run_diff_index(struct rev_info *revs, int cached);
 
-extern int do_diff_cache(const struct object_id *, struct diff_options *);
-extern int diff_flush_patch_id(struct diff_options *, struct object_id *, int);
+int do_diff_cache(const struct object_id *, struct diff_options *);
+int diff_flush_patch_id(struct diff_options *, struct object_id *, int);
 
-extern int diff_result_code(struct diff_options *, int);
+int diff_result_code(struct diff_options *, int);
 
-extern void diff_no_index(struct rev_info *, int, const char **);
+void diff_no_index(struct rev_info *, int, const char **);
 
-extern int index_differs_from(const char *def, const struct diff_flags *flags,
-			      int ita_invisible_in_index);
+int index_differs_from(const char *def, const struct diff_flags *flags,
+		       int ita_invisible_in_index);
 
 /*
  * Fill the contents of the filespec "df", respecting any textconv defined by

@@ -427,30 +427,30 @@ extern int index_differs_from(const char *def, const struct diff_flags *flags,
  * struct. If it is non-NULL, then "outbuf" points to a newly allocated buffer
  * that should be freed by the caller.
  */
-extern size_t fill_textconv(struct userdiff_driver *driver,
-			    struct diff_filespec *df,
-			    char **outbuf);
+size_t fill_textconv(struct userdiff_driver *driver,
+		     struct diff_filespec *df,
+		     char **outbuf);
 
 /*
  * Look up the userdiff driver for the given filespec, and return it if
  * and only if it has textconv enabled (otherwise return NULL). The result
  * can be passed to fill_textconv().
  */
-extern struct userdiff_driver *get_textconv(struct diff_filespec *one);
+struct userdiff_driver *get_textconv(struct diff_filespec *one);
 
 /*
  * Prepare diff_filespec and convert it using diff textconv API
  * if the textconv driver exists.
  * Return 1 if the conversion succeeds, 0 otherwise.
  */
-extern int textconv_object(const char *path, unsigned mode, const struct object_id *oid, int oid_valid, char **buf, unsigned long *buf_size);
+int textconv_object(const char *path, unsigned mode, const struct object_id *oid, int oid_valid, char **buf, unsigned long *buf_size);
 
-extern int parse_rename_score(const char **cp_p);
+int parse_rename_score(const char **cp_p);
 
-extern long parse_algorithm_value(const char *value);
+long parse_algorithm_value(const char *value);
 
-extern void print_stat_summary(FILE *fp, int files,
-			       int insertions, int deletions);
-extern void setup_diff_pager(struct diff_options *);
+void print_stat_summary(FILE *fp, int files,
+			int insertions, int deletions);
+void setup_diff_pager(struct diff_options *);
 
 #endif /* DIFF_H */

index 83ba3c25e8..d3c54e45aa 100644
@@ -19,11 +19,11 @@
 
 typedef const char *(*nth_line_fn_t)(void *data, long lno);
 
-extern int parse_range_arg(const char *arg,
-			   nth_line_fn_t nth_line_cb,
-			   void *cb_data, long lines, long anchor,
-			   long *begin, long *end,
-			   const char *path);
+int parse_range_arg(const char *arg,
+		    nth_line_fn_t nth_line_cb,
+		    void *cb_data, long lines, long anchor,
+		    long *begin, long *end,
+		    const char *path);
 
 /*
  * Scan past a range argument that could be parsed by

@@ -34,6 +34,6 @@ extern int parse_range_arg(const char *arg,
  * NULL in case the argument is obviously malformed.
  */
 
-extern const char *skip_range_arg(const char *arg);
+const char *skip_range_arg(const char *arg);
 
 #endif /* LINE_RANGE_H */

index c2961feaaa..cd948f28f4 100644
@@ -22,19 +22,19 @@ struct rerere_id {
 	int variant;
 };
 
-extern int setup_rerere(struct string_list *, int);
-extern int rerere(int);
+int setup_rerere(struct string_list *, int);
+int rerere(int);
 /*
  * Given the conflict ID and the name of a "file" used for replaying
  * the recorded resolution (e.g. "preimage", "postimage"), return the
  * path to that filesystem entity.  With "file" specified with NULL,
  * return the path to the directory that houses these files.
  */
-extern const char *rerere_path(const struct rerere_id *, const char *file);
-extern int rerere_forget(struct pathspec *);
-extern int rerere_remaining(struct string_list *);
-extern void rerere_clear(struct string_list *);
-extern void rerere_gc(struct string_list *);
+const char *rerere_path(const struct rerere_id *, const char *file);
+int rerere_forget(struct pathspec *);
+int rerere_remaining(struct string_list *);
+void rerere_clear(struct string_list *);
+void rerere_gc(struct string_list *);
 
 #define OPT_RERERE_AUTOUPDATE(v) OPT_UYN(0, "rerere-autoupdate", (v), \
 	N_("update the index with reused conflict resolution if possible"))

index f2646f0c52..f60d1cafbd 100644
@@ -94,19 +94,16 @@ struct set_gitdir_args {
 	const char *alternate_db;
 };
 
-extern void repo_set_gitdir(struct repository *repo,
-			    const char *root,
-			    const struct set_gitdir_args *extra_args);
-extern void repo_set_worktree(struct repository *repo, const char *path);
-extern void repo_set_hash_algo(struct repository *repo, int algo);
-extern void initialize_the_repository(void);
-extern int repo_init(struct repository *r,
-		     const char *gitdir,
-		     const char *worktree);
-extern int repo_submodule_init(struct repository *submodule,
-			       struct repository *superproject,
-			       const char *path);
-extern void repo_clear(struct repository *repo);
+void repo_set_gitdir(struct repository *repo, const char *root,
+		     const struct set_gitdir_args *extra_args);
+void repo_set_worktree(struct repository *repo, const char *path);
+void repo_set_hash_algo(struct repository *repo, int algo);
+void initialize_the_repository(void);
+int repo_init(struct repository *r, const char *gitdir, const char *worktree);
+int repo_submodule_init(struct repository *submodule,
+			struct repository *superproject,
+			const char *path);
+void repo_clear(struct repository *repo);
 
 /*
  * Populates the repository's index from its index_file, an index struct will

@@ -116,6 +113,6 @@ extern void repo_clear(struct repository *repo);
  * than zero if an error occured.  If the repository's index has already been
  * populated then the number of entries will simply be returned.
  */
-extern int repo_read_index(struct repository *repo);
+int repo_read_index(struct repository *repo);
 
 #endif /* REPOSITORY_H */

index b8c47b98e2..5f082a6d98 100644
@@ -226,7 +226,7 @@ struct rev_info {
 	const char *break_bar;
 };
 
-extern int ref_excluded(struct string_list *, const char *path);
+int ref_excluded(struct string_list *, const char *path);
 void clear_ref_exclusion(struct string_list **);
 void add_ref_exclusion(struct string_list **, const char *exclude);
 

@@ -248,39 +248,39 @@ struct setup_revision_opt {
 	unsigned revarg_opt;
 };
 
-extern void init_revisions(struct rev_info *revs, const char *prefix);
-extern int setup_revisions(int argc, const char **argv, struct rev_info *revs,
-			   struct setup_revision_opt *);
-extern void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
-			       const struct option *options,
-			       const char * const usagestr[]);
+void init_revisions(struct rev_info *revs, const char *prefix);
+int setup_revisions(int argc, const char **argv, struct rev_info *revs,
+		    struct setup_revision_opt *);
+void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
+			const struct option *options,
+			const char * const usagestr[]);
 #define REVARG_CANNOT_BE_FILENAME 01
 #define REVARG_COMMITTISH 02
-extern int handle_revision_arg(const char *arg, struct rev_info *revs,
-			       int flags, unsigned revarg_opt);
+int handle_revision_arg(const char *arg, struct rev_info *revs,
+			int flags, unsigned revarg_opt);
 
-extern void reset_revision_walk(void);
-extern int prepare_revision_walk(struct rev_info *revs);
-extern struct commit *get_revision(struct rev_info *revs);
-extern char *get_revision_mark(const struct rev_info *revs,
-			       const struct commit *commit);
-extern void put_revision_mark(const struct rev_info *revs,
-			      const struct commit *commit);
+void reset_revision_walk(void);
+int prepare_revision_walk(struct rev_info *revs);
+struct commit *get_revision(struct rev_info *revs);
+char *get_revision_mark(const struct rev_info *revs,
+			const struct commit *commit);
+void put_revision_mark(const struct rev_info *revs,
+		       const struct commit *commit);
 
-extern void mark_parents_uninteresting(struct commit *commit);
-extern void mark_tree_uninteresting(struct tree *tree);
+void mark_parents_uninteresting(struct commit *commit);
+void mark_tree_uninteresting(struct tree *tree);
 
-extern void show_object_with_name(FILE *, struct object *, const char *);
+void show_object_with_name(FILE *, struct object *, const char *);
 
-extern void add_pending_object(struct rev_info *revs,
-			       struct object *obj, const char *name);
-extern void add_pending_oid(struct rev_info *revs,
-			    const char *name, const struct object_id *oid,
-			    unsigned int flags);
+void add_pending_object(struct rev_info *revs,
+			struct object *obj, const char *name);
+void add_pending_oid(struct rev_info *revs,
+		     const char *name, const struct object_id *oid,
+		     unsigned int flags);
 
-extern void add_head_to_pending(struct rev_info *);
-extern void add_reflogs_to_pending(struct rev_info *, unsigned int flags);
-extern void add_index_objects_to_pending(struct rev_info *, unsigned int flags);
+void add_head_to_pending(struct rev_info *);
+void add_reflogs_to_pending(struct rev_info *, unsigned int flags);
+void add_index_objects_to_pending(struct rev_info *, unsigned int flags);
 
 enum commit_action {
 	commit_ignore,

@@ -288,10 +288,10 @@ enum commit_action {
 	commit_error
 };
 
-extern enum commit_action get_commit_action(struct rev_info *revs,
-					    struct commit *commit);
-extern enum commit_action simplify_commit(struct rev_info *revs,
-					  struct commit *commit);
+enum commit_action get_commit_action(struct rev_info *revs,
+				     struct commit *commit);
+enum commit_action simplify_commit(struct rev_info *revs,
+				   struct commit *commit);
 
 enum rewrite_result {
 	rewrite_one_ok,

@@ -301,8 +301,9 @@ enum rewrite_result {
 
 typedef enum rewrite_result (*rewrite_parent_fn_t)(struct rev_info *revs, struct commit **pp);
 
-extern int rewrite_parents(struct rev_info *revs, struct commit *commit,
-	rewrite_parent_fn_t rewrite_parent);
+int rewrite_parents(struct rev_info *revs,
+		    struct commit *commit,
+		    rewrite_parent_fn_t rewrite_parent);
 
 /*
  * The log machinery saves the original parent list so that

@@ -313,6 +314,6 @@ extern int rewrite_parents(struct rev_info *revs, struct commit *commit,
  * get_saved_parents() will transparently return commit->parents if
  * history simplification is off.
  */
-extern struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit);
+struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit);
 
 #endif

index 7856b8a0b3..d266e6dca5 100644
@@ -33,62 +33,62 @@ struct submodule_update_strategy {
 };
 #define SUBMODULE_UPDATE_STRATEGY_INIT {SM_UPDATE_UNSPECIFIED, NULL}
 
-extern int is_gitmodules_unmerged(const struct index_state *istate);
-extern int is_staging_gitmodules_ok(struct index_state *istate);
-extern int update_path_in_gitmodules(const char *oldpath, const char *newpath);
-extern int remove_path_from_gitmodules(const char *path);
-extern void stage_updated_gitmodules(struct index_state *istate);
-extern void set_diffopt_flags_from_submodule_config(struct diff_options *,
-		const char *path);
-extern int git_default_submodule_config(const char *var, const char *value, void *cb);
+int is_gitmodules_unmerged(const struct index_state *istate);
+int is_staging_gitmodules_ok(struct index_state *istate);
+int update_path_in_gitmodules(const char *oldpath, const char *newpath);
+int remove_path_from_gitmodules(const char *path);
+void stage_updated_gitmodules(struct index_state *istate);
+void set_diffopt_flags_from_submodule_config(struct diff_options *,
+					     const char *path);
+int git_default_submodule_config(const char *var, const char *value, void *cb);
 
 struct option;
 int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
 						     const char *arg, int unset);
-extern int is_submodule_active(struct repository *repo, const char *path);
+int is_submodule_active(struct repository *repo, const char *path);
 /*
  * Determine if a submodule has been populated at a given 'path' by checking if
  * the <path>/.git resolves to a valid git repository.
  * If return_error_code is NULL, die on error.
  * Otherwise the return error code is the same as of resolve_gitdir_gently.
  */
-extern int is_submodule_populated_gently(const char *path, int *return_error_code);
-extern void die_in_unpopulated_submodule(const struct index_state *istate,
-					 const char *prefix);
-extern void die_path_inside_submodule(const struct index_state *istate,
-				      const struct pathspec *ps);
-extern enum submodule_update_type parse_submodule_update_type(const char *value);
-extern int parse_submodule_update_strategy(const char *value,
-		struct submodule_update_strategy *dst);
-extern const char *submodule_strategy_to_string(const struct submodule_update_strategy *s);
-extern void handle_ignore_submodules_arg(struct diff_options *, const char *);
-extern void show_submodule_summary(struct diff_options *o, const char *path,
-		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule);
-extern void show_submodule_inline_diff(struct diff_options *o, const char *path,
-		struct object_id *one, struct object_id *two,
-		unsigned dirty_submodule);
+int is_submodule_populated_gently(const char *path, int *return_error_code);
+void die_in_unpopulated_submodule(const struct index_state *istate,
+				  const char *prefix);
+void die_path_inside_submodule(const struct index_state *istate,
+			       const struct pathspec *ps);
+enum submodule_update_type parse_submodule_update_type(const char *value);
+int parse_submodule_update_strategy(const char *value,
+				    struct submodule_update_strategy *dst);
+const char *submodule_strategy_to_string(const struct submodule_update_strategy *s);
+void handle_ignore_submodules_arg(struct diff_options *, const char *);
+void show_submodule_summary(struct diff_options *o, const char *path,
+			    struct object_id *one, struct object_id *two,
+			    unsigned dirty_submodule);
+void show_submodule_inline_diff(struct diff_options *o, const char *path,
+				struct object_id *one, struct object_id *two,
+				unsigned dirty_submodule);
 /* Check if we want to update any submodule.*/
-extern int should_update_submodules(void);
+int should_update_submodules(void);
 /*
  * Returns the submodule struct if the given ce entry is a submodule
  * and it should be updated. Returns NULL otherwise.
  */
-extern const struct submodule *submodule_from_ce(const struct cache_entry *ce);
-extern void check_for_new_submodule_commits(struct object_id *oid);
-extern int fetch_populated_submodules(struct repository *r,
-				      const struct argv_array *options,
-				      const char *prefix,
-				      int command_line_option,
-				      int default_option,
-				      int quiet, int max_parallel_jobs);
-extern unsigned is_submodule_modified(const char *path, int ignore_untracked);
-extern int submodule_uses_gitfile(const char *path);
+const struct submodule *submodule_from_ce(const struct cache_entry *ce);
+void check_for_new_submodule_commits(struct object_id *oid);
+int fetch_populated_submodules(struct repository *r,
+			       const struct argv_array *options,
+			       const char *prefix,
+			       int command_line_option,
+			       int default_option,
+			       int quiet, int max_parallel_jobs);
+unsigned is_submodule_modified(const char *path, int ignore_untracked);
+int submodule_uses_gitfile(const char *path);
 
 #define SUBMODULE_REMOVAL_DIE_ON_ERROR (1<<0)
 #define SUBMODULE_REMOVAL_IGNORE_UNTRACKED (1<<1)
 #define SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED (1<<2)
-extern int bad_to_remove_submodule(const char *path, unsigned flags);
+int bad_to_remove_submodule(const char *path, unsigned flags);
 
 int add_submodule_odb(const char *path);
 

@@ -96,17 +96,17 @@ int add_submodule_odb(const char *path);
  * Checks if there are submodule changes in a..b. If a is the null OID,
  * checks b and all its ancestors instead.
  */
-extern int submodule_touches_in_range(struct object_id *a,
-				      struct object_id *b);
-extern int find_unpushed_submodules(struct oid_array *commits,
-				    const char *remotes_name,
-				    struct string_list *needs_pushing);
+int submodule_touches_in_range(struct object_id *a,
+			       struct object_id *b);
+int find_unpushed_submodules(struct oid_array *commits,
+			     const char *remotes_name,
+			     struct string_list *needs_pushing);
 struct refspec;
-extern int push_unpushed_submodules(struct oid_array *commits,
-				    const struct remote *remote,
-				    const struct refspec *rs,
-				    const struct string_list *push_options,
-				    int dry_run);
+int push_unpushed_submodules(struct oid_array *commits,
+			     const struct remote *remote,
+			     const struct refspec *rs,
+			     const struct string_list *push_options,
+			     int dry_run);
 /*
  * Given a submodule path (as in the index), return the repository
  * path of that submodule in 'buf'. Return -1 on error or when the

@@ -116,28 +116,28 @@ int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 #define SUBMODULE_MOVE_HEAD_DRY_RUN (1<<0)
 #define SUBMODULE_MOVE_HEAD_FORCE   (1<<1)
-extern int submodule_move_head(const char *path,
-			       const char *old,
-			       const char *new_head,
-			       unsigned flags);
+int submodule_move_head(const char *path,
+			const char *old,
+			const char *new_head,
+			unsigned flags);
 
 /*
  * Prepare the "env_array" parameter of a "struct child_process" for executing
  * a submodule by clearing any repo-specific environment variables, but
  * retaining any config in the environment.
  */
-extern void prepare_submodule_repo_env(struct argv_array *out);
+void prepare_submodule_repo_env(struct argv_array *out);
 
 #define ABSORB_GITDIR_RECURSE_SUBMODULES (1<<0)
-extern void absorb_git_dir_into_superproject(const char *prefix,
-					     const char *path,
-					     unsigned flags);
+void absorb_git_dir_into_superproject(const char *prefix,
+				      const char *path,
+				      unsigned flags);
 
 /*
  * Return the absolute path of the working tree of the superproject, which this
  * project is a submodule of. If this repository is not a submodule of
  * another repository, return NULL.
  */
-extern const char *get_superproject_working_tree(void);
+const char *get_superproject_working_tree(void);
 
 #endif