add for unix port

src/lib9/utf/plan9.h

@@ -0,0 +1,29 @@
+/*
+ * compiler directive on Plan 9
+ */
+#ifndef USED
+#define USED(x) if(x);else
+#endif
+
+/*
+ * easiest way to make sure these are defined
+ */
+#define uchar	_utfuchar
+#define ushort	_utfushort
+#define uint	_utfuint
+#define ulong	_utfulong
+typedef unsigned char		uchar;
+typedef unsigned short		ushort;
+typedef unsigned int		uint;
+typedef unsigned long		ulong;
+
+/*
+ * nil cannot be ((void*)0) on ANSI C,
+ * because it is used for function pointers
+ */
+#undef	nil
+#define	nil	0
+
+#undef	nelem
+#define	nelem(x)	(sizeof (x)/sizeof (x)[0])
+