describe: when failing, tell the user about options that work

diff --git a/xdiff-interface.c b/xdiff-interface.c
index b9b0db8d86615d6ca1046b932772f3d9750a8062..01f14fb50f7cf1387898a0c8db44f966ce07b720 100644 (file)
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -309,6 +309,21 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
        }
 }
 
+void xdiff_clear_find_func(xdemitconf_t *xecfg)
+{
+       if (xecfg->find_func) {
+               int i;
+               struct ff_regs *regs = xecfg->find_func_priv;
+
+               for (i = 0; i < regs->nr; i++)
+                       regfree(&regs->array[i].re);
+               free(regs->array);
+               free(regs);
+               xecfg->find_func = NULL;
+               xecfg->find_func_priv = NULL;
+       }
+}
+
 int git_xmerge_style = -1;
 
 int git_xmerge_config(const char *var, const char *value, void *cb)