make relative paths wasnt working, also disallowed it when the blend file isnt saved

source/blender/blenlib/intern/bpath.c

@@ -345,7 +345,7 @@ void makeFilesRelative(int *tot, int *changed, int *failed, int *linked) {
 		filepath = BLI_bpathIterator_getPath(&bpi);
 		libpath = BLI_bpathIterator_getLib(&bpi);
 		
-		if(strncmp(filepath, "//", 2)==0) {
+		if(strncmp(filepath, "//", 2)) {
 			if (libpath) { /* cant make relative if we are kibrary - TODO, LOG THIS */
 				(*linked)++;
 			} else { /* local data, use the blend files path */
@@ -356,10 +356,10 @@ void makeFilesRelative(int *tot, int *changed, int *failed, int *linked) {
 				} else {
 					/* safe to to check the length */
 					if(strncmp(filepath_relative, "//", 2)==0) {
-						(*failed)++;
-					} else {
 						strcpy(filepath, filepath_relative);
 						(*changed)++;
+					} else {
+						(*failed)++;
 					}
 				}
 			}

source/blender/src/header_info.c

@@ -953,12 +953,14 @@ static void do_info_externalfiles(void *arg, int event)
 		}
 		break;
 	case 10: /* make all paths relative */
-		{
+		if (G.relbase_valid) {
 			int tot,changed,failed,linked;
 			char str[512];
 			makeFilesRelative(&tot, &changed, &failed, &linked);
 			sprintf(str, "Make Relative%%t|Total files %i|Changed %i|Failed %i|Linked %i", tot, changed, failed, linked);
 			pupmenu(str);
+		} else {
+			pupmenu("Can't set relative paths with an unsaved blend file");
 		}
 		break;
 	case 11: /* check images exist */