gislib: print error when fork() fails

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@71549 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/gis/spawn.c

@@ -663,7 +663,7 @@ static int do_spawn(struct spawn *sp, const char *command)
 
     pid = fork();
     if (pid < 0) {
-	G_warning(_("Unable to create a new process"));
+	G_warning(_("Unable to create a new process: %s"), strerror(errno));
 	undo_signals(sp->signals, sp->num_signals, SST_PRE);
 
 	return status;