compiler: load imports and enforce package exports

cmd/wcc/ww.h

@@ -383,6 +383,9 @@ struct Parser {
 
 void	parserinit(Parser*, Arena*, Lex*);
 Node	*parsefile(Parser*);
+/* Imports-only N_FILE: module/pos identify the first package clause,
+ * list holds N_USE declarations, and body holds package-clause markers. */
+Node	*parseimports(Parser*);
 Node	*parseexpr_top(Parser*);	/* for testing: parse one expression */
 
 typedef enum {
@@ -585,6 +588,10 @@ struct Checker {
 	int	errs;
 	int	is_test;	/* #15: `w6c -T` — collect @test fns + synth
 				 * the entry; loud-reject a user main. */
+	int	sep_mode;	/* -c package compilation: imported interfaces are
+				 * present, so absent members are hard export errors. */
+	Node	*synth_test_run;	/* exact compiler-generated test.run DOT;
+				 * its unresolved external hook is intentional */
 	Node	*alloc_octx;	/* #3/B': the one empty `alloc([], n)` call node
 				 * that has let-declared slice context this walk;
 				 * any OTHER empty alloc has no element-type hint