add a Makefile switch to avoid gettext translation in shell scripts

Some systems have gettext.sh (GNU gettext) installed, but it is either
broken or misconfigured in such a way so its output is not usable.  In
case the users of these systems are unable or not interested in fixing
them, setting the new Makefile switch should help:

    make USE_GETTEXT_SCHEME=fallthrough

This will replace the translation routines with fallthrough versions,
that does not use gettext from the platform.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -47,6 +47,9 @@ all::
 # A translated Git requires GNU libintl or another gettext implementation,
 # plus libintl-perl at runtime.
 #
+# Define USE_GETTEXT_SCHEME and set it to 'fallthrough', if you don't trust
+# the installed gettext translation of the shell scripts output.
+#
 # Define HAVE_LIBCHARSET_H if you haven't set NO_GETTEXT and you can't
 # trust the langinfo.h's nl_langinfo(CODESET) function to return the
 # current character set. GNU and Solaris have a nl_langinfo(CODESET),
@@ -1874,6 +1877,7 @@ sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
     -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
     -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
     -e 's/@@NO_CURL@@/$(NO_CURL)/g' \
+    -e 's/@@USE_GETTEXT_SCHEME@@/$(USE_GETTEXT_SCHEME)/g' \
     -e $(BROKEN_PATH_FIX) \
     $@.sh >$@+
 endef
@@ -2251,7 +2255,7 @@ cscope:
 ### Detect prefix changes
 TRACK_CFLAGS = $(CC):$(subst ','\'',$(ALL_CFLAGS)):\
              $(bindir_SQ):$(gitexecdir_SQ):$(template_dir_SQ):$(prefix_SQ):\
-             $(localedir_SQ)
+             $(localedir_SQ):$(USE_GETTEXT_SCHEME)
 
 GIT-CFLAGS: FORCE
 	@FLAGS='$(TRACK_CFLAGS)'; \

git-sh-i18n.sh

@@ -18,7 +18,10 @@ export TEXTDOMAINDIR
 
 # First decide what scheme to use...
 GIT_INTERNAL_GETTEXT_SH_SCHEME=fallthrough
-if test -n "$GIT_INTERNAL_GETTEXT_TEST_FALLBACKS"
+if test -n "@@USE_GETTEXT_SCHEME@@"
+then
+	GIT_INTERNAL_GETTEXT_SH_SCHEME="@@USE_GETTEXT_SCHEME@@"
+elif test -n "@@USE_FALLTHROUGH_GETTEXT_SCHEME@@$GIT_INTERNAL_GETTEXT_TEST_FALLBACKS"
 then
 	: no probing necessary
 elif test -n "$GIT_GETTEXT_POISON"