Symlink mergetools scriptlets into valgrind wrappers

Since bc7a96a (mergetool--lib: Refactor tools into separate files,
2011-08-18) the mergetools and difftools related tests fail under
--valgrind because the mergetools/* scriptlets are not in the exec
path.

For now, symlink the mergetools subdir into the t/valgrind/bin
directory as a whole, since it does not contain anything of interest
to the valgrind wrappers.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -932,6 +932,8 @@ then
 	do
 		make_valgrind_symlink $file
 	done
+	# special-case the mergetools loadables
+	make_symlink "$GIT_BUILD_DIR"/mergetools "$GIT_VALGRIND/bin/mergetools"
 	OLDIFS=$IFS
 	IFS=:
 	for path in $PATH