Fix one crash in the new Ctrl-Find feature (option lists can, unfortunately, be

terminated with a 0-length option string).
There still another crash I'm investigating that occurs if you type a string
that isn't found. It appears to deref past the end of the option array.

src/uifc/uifc32.c

@@ -1715,7 +1715,7 @@ int ulist(int mode, int left, int top, int width, int *cur, int *bar
 						case CTRL_G:
 							if(/*!(api->mode&UIFC_NOCTRL)*/1) { // No no, *this* control key is fine!
 								if (gotkey == CTRL_G || api->input(WIN_MID|WIN_SAV, 0, 0, "Find", search, sizeof(search), K_EDIT) > 0) {
-									for (j = (*cur) + 1; j != *cur; j++, j = option[j] == NULL ? 0 : j) {   /* a = search count */
+									for (j = (*cur) + 1; j != *cur; j++, j = (option[j] == NULL || !option[j][0]) ? 0 : j) {   /* a = search count */
 										if (strcasestr(option[j], search) != NULL) {
 											// Copy/pasted from search above.
 											if(y+(j-(*cur))+2>height+top) {