msgmerge: do not output to terminal when --updatemsgmerge-stub

i have a misunderstanding on --update, this argument is used to update
the original .po file. And because we just simply copy strings from
.po file, so we should just return 0, as we dont actually do anything to
.po file. when --update is passed, nothing should be printed on screen.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/msgmerge.c b/src/msgmerge.c
index fd01546..ae85934 100644
--- a/src/msgmerge.c
+++ b/src/msgmerge.c
@@ -225,6 +225,7 @@ int main(int argc, char**argv) {
 	}
 	if(update) {
 		fprintf(stdout, "warning: update functionality unimplemented\n");
+		return 0;
 	}
 	if(!files.out || !files.po || !files.pot) syntax();
 	int ret = process(&files, update, backup);