Fix crash when out of memory in Team Arena's String_Alloc

code/ui/ui_shared.c

@@ -198,6 +198,9 @@ const char *String_Alloc(const char *p) {
 		}
 
 		str  = UI_Alloc(sizeof(stringDef_t));
+		if (!str) {
+			return NULL;
+		}
 		str->next = NULL;
 		str->str = &strPool[ph];
 		if (last) {