compiler: load imports and enforce package exports

selfhost/cmd/w6c/main.ww

@@ -172,6 +172,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 	let ck: checker;
 	checkinit(&ck, &tc);
 	ck.istest = testmode;
+	ck.sepmode = sepmode;
 	checkfile(&ck, f);
 	if (ck.errs > 0) { return 1; };