do not define __offsetof twice

vlib/compiler/cheaders.v

@@ -21,8 +21,10 @@ const (
 #endif
 
 // for __offset_of
+#ifndef __offsetof
 #define __offsetof(s,memb) \\
     ((size_t)((char *)&((s *)0)->memb - (char *)0))
+#endif
 
 #define OPTION_CAST(x) (x)
 '

vlib/compiler/main.v

@@ -1056,7 +1056,7 @@ pub fn new_v(args []string) &V {
 		is_live: '-live' in args
 		sanitize: '-sanitize' in args
 		// nofmt: '-nofmt' in args
-		
+
 		show_c_cmd: '-show_c_cmd' in args
 		translated: 'translated' in args
 		is_run: 'run' in args
@@ -1075,7 +1075,7 @@ pub fn new_v(args []string) &V {
 		building_v: !is_repl && (rdir_name == 'compiler' || rdir_name == 'v.v' || dir.contains('vlib'))
 		comptime_define: comptime_define
 		// is_fmt: comptime_define == 'vfmt'
-		
+
 		user_mod_path: user_mod_path
 		vlib_path: vlib_path
 		vpath: vpath
@@ -1133,7 +1133,6 @@ pub fn env_vflags_and_os_args() []string {
 }
 
 pub fn vfmt(args []string) {
-	println('running vfmt...')
 	file := args.last()
 	if !os.exists(file) {
 		println('"$file" does not exist')
@@ -1147,11 +1146,13 @@ pub fn vfmt(args []string) {
 	// launch_tool('vfmt', '-d vfmt')
 	vroot := os.dir(vexe)
 	os.chdir(vroot)
+	println('building vfmt... (it will be cached soon)')
 	ret := os.system('$vexe -o $vroot/tools/vfmt -d vfmt v.v')
 	if ret != 0 {
 		println('err')
 		return
 	}
+	println('running vfmt...')
 	os.exec('$vroot/tools/vfmt $file')or{
 		panic(err)
 	}