builtin: Simplify linking with libgc

vlib/builtin/builtin_d_gcboehm.c.v

@@ -83,9 +83,7 @@ $if dynamic_boehm ? {
 							#flag @VEXEROOT/thirdparty/tcc/lib/libgc.a
 						}
 					} $else {
-						#flag -L@VEXEROOT/thirdparty/tcc/lib
-						#flag -lgc
-						#flag -Xlinker -rpath -Xlinker "@VEXEROOT/thirdparty/tcc/lib"
+						#flag @VEXEROOT/thirdparty/tcc/lib/libgc.a
 					}
 				} $else {
 					$if musl ? {

vlib/v/builder/gc_flags_test.v

@@ -220,6 +220,37 @@ fn test_macos_amd64_tcc_boehm_uses_bundled_libgc_dylib() {
 	assert run_res.exit_code == 0, run_res.output
 }
 
+fn test_macos_system_cc_boehm_uses_bundled_static_libgc() {
+	$if !macos {
+		return
+	}
+	test_root := os.join_path(os.vtmp_dir(), 'builder_gc_flags_system_cc_${os.getpid()}')
+	os.mkdir_all(test_root) or { panic(err) }
+	exe_path := os.join_path(test_root, 'hello_world')
+	source_path := os.join_path(@VEXEROOT, 'examples', 'hello_world.v')
+	archive_path := os.join_path(@VEXEROOT, 'thirdparty', 'tcc', 'lib', 'libgc.a')
+	defer {
+		os.rmdir_all(test_root) or {}
+	}
+	cmd := '${os.quoted_path(@VEXE)} -cc cc -gc boehm -showcc -no-retry-compilation -no-rsp -nocache -o ${os.quoted_path(exe_path)} ${os.quoted_path(source_path)}'
+	res := execute_without_vflags(cmd)
+	assert res.exit_code == 0, res.output
+	lines := res.output.split_into_lines().filter(it.starts_with(showcc_prefix))
+	assert lines.len == 1, res.output
+	tokens := tokenize_showcc_command(lines[0][showcc_prefix.len..]) or {
+		assert false, '${err.msg()}\n${res.output}'
+		return
+	}
+	assert count_showcc_token(tokens, archive_path) == 1, res.output
+	for token in tokens {
+		assert !token.contains('libgc.dylib'), res.output
+		assert !token.contains('rpath'), res.output
+		assert token != '-lgc', res.output
+	}
+	run_res := os.execute(os.quoted_path(exe_path))
+	assert run_res.exit_code == 0, run_res.output
+}
+
 fn test_linux_musl_tcc_boehm_uses_system_libgc() {
 	$if !linux {
 		return