compiler: load imports and enforce package exports

cmd/w6c/main.c

@@ -77,6 +77,7 @@ main(int argc, char **argv)
 
 	check_init(&c, a);
 	c.is_test = testmode;
+	c.sep_mode = sepmode;
 	check_file(&c, file);
 	if (c.errs) return 1;
 

cmd/w6c/wwi.c

@@ -543,8 +543,13 @@ wwi_emit(Checker *c, FILE *of, Node *file)
 			k++;
 		}
 		qsort(us, (size_t)nuse, sizeof *us, usecmp);
-		for (int i = 0; i < nuse; i++)
+		const char *previous = NULL;
+		for (int i = 0; i < nuse; i++) {
+			if (previous && strcmp(previous, us[i].path) == 0)
+				continue;
 			fprintf(of, "import %s;\n", us[i].path);
+			previous = us[i].path;
+		}
 		free(us);
 	}