gitk: Fix the Makefile to cope with systems lacking msgfmt

The po2msg.sh script and the .gitignore in the po directory have been shamelessly copied from the current git-gui. This enables the top level "make NO_MSGFMT" to work consistently for git across the git-gui and gitk sub-projects.

This is the same effective patch that has previously been posted as a git.git patch which more succinctly described the copying of po/.gitignore and po/po2msg.sh from git-gui.

---
 Makefile      |    7 +++-
 po/.gitignore |    2 +
 po/po2msg.sh  |  133 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 141 insertions(+), 1 deletions(-)
 create mode 100644 po/.gitignore
 create mode 100644 po/po2msg.sh

index 6158504..ae2b80b 100644
@@ -18,7 +18,12 @@ TCLTK_PATH_SQ = $(subst ','\'',$(TCLTK_PATH))
 
 ## po-file creation rules
 XGETTEXT   ?= xgettext
-MSGFMT     ?= msgfmt
+ifdef NO_MSGFMT
+	MSGFMT ?= $(TCL_PATH) po/po2msg.sh
+else
+	MSGFMT ?= msgfmt
+endif
+
 PO_TEMPLATE = po/gitk.pot
 ALL_POFILES = $(wildcard po/*.po)
 ALL_MSGFILES = $(subst .po,.msg,$(ALL_POFILES))

new file mode 100644
index 0000000..a89cf44
@@ -0,0 +1,2 @@
+*.msg
+*~

1.5.4.rc2.60.gb2e62