compiler: make package exports self-contained

selfhost/cmd/wcc/cgen.ww

@@ -4012,6 +4012,14 @@ fn ffiresolve(c: *cgen, ident: str) str = {
 	return ident;
 };
 
+// The compiler intrinsic `alloc` has a package-mode runtime ABI independent
+// of whichever transitive interfaces happen to be present. Raw w6c remains
+// declaration-driven so existing @symbol/FFI behavior is unchanged.
+fn allocresolve(c: *cgen) str = {
+	if (c.sepmode != 0) { return "rt_malloc"; };
+	return ffiresolve(c, "malloc");
+};
+
 fn argregname(i: i32) str = {
 	if (i == 0) { return "DI"; };
 	if (i == 1) { return "SI"; };