Small tweaks

Lots of new code imported.

src/lib9p/post.c

@@ -0,0 +1,24 @@
+#include <u.h>
+#include <libc.h>
+#include <fcall.h>
+#include <thread.h>
+#include <9p.h>
+#include "post.h"
+
+void
+postmountsrv(Srv *s, char *name, char *mtpt, int flag)
+{
+	Postcrud *p;
+
+	p = _post1(s, name, mtpt, flag);
+	switch(rfork(RFPROC|RFNOTEG|RFNAMEG|RFMEM)){
+	case -1:
+		sysfatal("rfork: %r");
+	case 0:
+		_post2(s);
+		exits(nil);
+	default:
+		_post3(p);
+	}
+}
+