gettext: add patch to fix --for-msgfmt

Fix behaviour of --for-msgfmt on PO files with no translations.

pkgs/development/libraries/gettext/default.nix

@@ -10,6 +10,7 @@ stdenv.mkDerivation rec {
   };
   patches = [
     ./absolute-paths.diff
+    ./gettext.git-2336451ed68d91ff4b5ae1acbc1eca30e47a86a9.patch
   ];
 
   outputs = [ "out" "man" "doc" "info" ];

pkgs/development/libraries/gettext/gettext.git-2336451ed68d91ff4b5ae1acbc1eca30e47a86a9.patch

@@ -0,0 +1,82 @@
+From 2336451ed68d91ff4b5ae1acbc1eca30e47a86a9 Mon Sep 17 00:00:00 2001
+From: Bruno Haible <bruno@clisp.org>
+Date: Sun, 19 May 2019 13:10:06 +0200
+Subject: [PATCH] msgmerge: Fix behaviour of --for-msgfmt on PO files with no
+ translations.
+
+Reported by Don Lawrence <dlawrence@iecok.com>
+in <https://lists.freedesktop.org/archives/p11-glue/2019-May/000700.html>
+via Daiki Ueno
+in <https://lists.gnu.org/archive/html/bug-gettext/2019-05/msg00124.html>.
+
+* gettext-tools/src/msgmerge.c (main): Treat force_po like true if for_msgfmt
+is true.
+* gettext-tools/tests/msgmerge-26: Add test of PO file with no translations.
+---
+ gettext-tools/src/msgmerge.c    |  4 ++--
+ gettext-tools/tests/msgmerge-26 | 36 +++++++++++++++++++++++++++++++++---
+ 2 files changed, 35 insertions(+), 5 deletions(-)
+
+diff --git a/gettext-tools/src/msgmerge.c b/gettext-tools/src/msgmerge.c
+index cd762c0..92c9b7a 100644
+--- a/gettext-tools/src/msgmerge.c
++++ b/gettext-tools/src/msgmerge.c
+@@ -520,8 +520,8 @@ There is NO WARRANTY, to the extent permitted by law.\n\
+   else
+     {
+       /* Write the merged message list out.  */
+-      msgdomain_list_print (result, output_file, output_syntax, force_po,
+-                            false);
++      msgdomain_list_print (result, output_file, output_syntax,
++                            for_msgfmt || force_po, false);
+     }
+ 
+   exit (EXIT_SUCCESS);
+diff --git a/gettext-tools/tests/msgmerge-26 b/gettext-tools/tests/msgmerge-26
+index cd3862e..b86f7a0 100755
+--- a/gettext-tools/tests/msgmerge-26
++++ b/gettext-tools/tests/msgmerge-26
+@@ -73,7 +73,37 @@ msgstr "Papaya"
+ EOF
+ 
+ : ${DIFF=diff}
+-${DIFF} mm-test26.ok mm-test26.out
+-result=$?
++${DIFF} mm-test26.ok mm-test26.out || Exit 1
+ 
+-exit $result
++# Test with a PO file that has no translated messages.
++
++cat <<\EOF > mm-test26a.in1
++msgid ""
++msgstr ""
++"Content-Type: text/plain; charset=UTF-8\n"
++
++msgid "Hello world"
++msgstr "Hallo Welt"
++EOF
++
++cat <<\EOF > mm-test26a.in2
++msgid ""
++msgstr ""
++"Content-Type: text/plain; charset=ASCII\n"
++
++msgid "Hello, world!"
++msgstr ""
++EOF
++
++: ${MSGMERGE=msgmerge}
++${MSGMERGE} --for-msgfmt -o mm-test26a.tmp mm-test26a.in1 mm-test26a.in2 \
++    || Exit 1
++LC_ALL=C tr -d '\r' < mm-test26a.tmp > mm-test26a.out || Exit 1
++
++cat <<\EOF > mm-test26a.ok
++msgid ""
++msgstr "Content-Type: text/plain; charset=UTF-8\n"
++EOF
++
++: ${DIFF=diff}
++${DIFF} mm-test26a.ok mm-test26a.out || Exit 1
+-- 
+1.9.1
+