push a null symbol as a terminator for /alternatename weak symbol chain

src/linker/lnk.c

@@ -462,7 +462,10 @@ lnk_make_null_obj(Arena *arena)
 {
   COFF_ObjWriter *obj_writer = coff_obj_writer_alloc(0,COFF_MachineType_Unknown);
 
-  // make import stub
+  // push null symbol
+  coff_obj_writer_push_symbol_abs(obj_writer, str8_lit(LNK_NULL_SYMBOL), 0, COFF_SymStorageClass_External);
+
+  // push import stub
   {
     COFF_ObjSymbol *tag = coff_obj_writer_push_symbol_abs(obj_writer, str8_lit("RAD_IMPORT_STUB_NULL"), 0, COFF_SymStorageClass_Static);
     coff_obj_writer_push_symbol_weak(obj_writer, str8_lit(LNK_IMPORT_STUB), COFF_WeakExt_AntiDependency, tag);

src/linker/lnk.h

@@ -6,6 +6,7 @@
 // --- Link --------------------------------------------------------------------
 
 #define LNK_IMPORT_STUB "*** RAD_IMPORT_STUB ***"
+#define LNK_NULL_SYMBOL "*** RAD_NULL_SYMBOL ***"
 #define LNK_SECTION_FLAG_IS_LIVE (1 << 0)
 
 typedef struct LNK_LinkContext