Save errno in handle_alias()

git.c:main() relies on the value of errno being set by the last attempt to
execute the command. However, if something goes awry in handle_alias(),
that assumption is wrong. So restore errno before returning from
handle_alias().

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git.c

@@ -100,7 +100,7 @@ static int split_cmdline(char *cmdline, const char ***argv)
 
 static int handle_alias(int *argcp, const char ***argv)
 {
-	int nongit = 0, ret = 0;
+	int nongit = 0, ret = 0, saved_errno = errno;
 	const char *subdir;
 
 	subdir = setup_git_directory_gently(&nongit);
@@ -138,6 +138,8 @@ static int handle_alias(int *argcp, const char ***argv)
 	if (subdir)
 		chdir(subdir);
 
+	errno = saved_errno;
+
 	return ret;
 }