cgen_test: skip empty lines; os: make vc_gen compile

vlib/os/os_nix.v

@@ -216,3 +216,29 @@ pub fn symlink(origin, target string) ?bool {
 	if res == 0 { return true }
 	return error(get_error_msg(C.errno))
 }
+
+// convert any value to []byte (LittleEndian) and write it
+// for example if we have write(7, 4), "07 00 00 00" gets written
+// write(0x1234, 2) => "34 12"
+pub fn (f mut File) write_bytes(data voidptr, size int) {
+	$if linux {
+		C.syscall(sys_write, f.fd,  data, 1)
+	} $else {
+		C.fwrite(data, 1, size, f.cfile)
+	}
+}
+
+pub fn (f mut File) close() {
+	if !f.opened {
+		return
+	}
+	f.opened = false
+	$if linux {
+	//$if linux_or_macos {
+		C.syscall(sys_close, f.fd)
+		return
+	}
+	C.fflush(f.cfile)
+	C.fclose(f.cfile)
+}
+