Centralise fault handling

This should be done as all platforms essentially did the same anyway and there was nothing platform specific.

XAlloc.c

@@ -14,7 +14,7 @@
 void fail() {
    curs_set(1);
    endwin();
-   err(1, NULL);
+   abort();
 }
 
 void* xMalloc(size_t size) {