[gimp] app: don't use GNU-only options when generating git-version.h

[Michael Natterer <mitch src gnome org>]

commit 29a6c71f002aed4845479f9b46cdb2cdf58bc623
Author: Michael Natterer <mitch gimp org>
Date:   Tue Oct 4 23:36:21 2011 +0200

    app: don't use GNU-only options when generating git-version.h

 app/Makefile.am |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/app/Makefile.am b/app/Makefile.am
index 92167a8..7122989 100644
--- a/app/Makefile.am
+++ b/app/Makefile.am
@@ -274,12 +274,11 @@ dist-hook: dist-check-gimp-console dist-dump-gimprc
 git-version.h: update-git-version-header
 	@if test -d "$(top_srcdir)/.git"; then \
 	  git_version="`git --git-dir=$(top_srcdir)/.git describe --always`"; \
-	  git_last_commit_timestamp="`git --git-dir=$(top_srcdir)/.git log -n1 --reverse --pretty=%ct`"; \
-	  git_last_commit_year="`date --utc -d \"1970-01-01 + $$git_last_commit_timestamp seconds\" '+%Y'`"; \
+	  git_last_commit_year="`git --git-dir=$(top_srcdir)/.git log -n1 --reverse --pretty=%ci | cut -b 1-4`"; \
 	elif test ! -f "$@"; then \
 	  git_version="Unknown, shouldn't happen"; \
 	  git_last_commit_timestamp=-1; \
-	  git_last_commit_year="`date --utc '+%Y'`"; \
+	  git_last_commit_year="`date -u '+%Y'`"; \
 	fi; \
 	if test -n "$$git_version"; then \
 	  echo "#ifndef __GIT_VERSION_H__" > "$  tmp"; \