kbuild: Get more focus on warnings

The following patch put focus on warnings when compiling.

Kbuild has for a long period supported a quit mode. The quit mode prints a single line for each file compiled, thus warnings becomes much more visible.
Example:

CC kernel/uid16.o
CC kernel/ksyms.o
kernel/ksyms.c:441: warning: `__check_region' is deprecated (declared at include/linux/ioport.h:113)
CC kernel/module.o

The old output format can obtained like this:

	$ make V=1

or more permanent with the following assignment in .bashrc:
KBUILD_VERBOSE=1

If one is concerned about warnings the output from a kernel build is redirected to a file, or make -s is used.
The advantage of this patch is that the default settings puts focus on warnings while still providing the user with feedback about the build process.

Kai Germaschewski has done most of the initial work enabling this feature, originally inspired from Keith Owens kbuild-2.5 patchset.

Sam

OK, here is the patch.

Sam

===== Makefile 1.406 vs edited =====

@@ -107,7 +107,7 @@
 # If it is set to "silent_", nothing wil be printed at all, since
 # the variable $(silent_cmd_cc_o_c) doesn't exist.
 
-#	For now, leave verbose as default
+# To put more focus on warnings, less verbose as default
 
 ifdef V
   ifeq ("$(origin V)", "command line")

@@ -115,7 +115,7 @@
   endif
 endif
 ifndef KBUILD_VERBOSE
-  KBUILD_VERBOSE = 1
+  KBUILD_VERBOSE = 0 
 endif
 
 ifdef C