INSTALL: fix build on Snow Leopard

http://codereview.appspot.com/116073

src/cmd/eqn/e.h

@@ -18,6 +18,8 @@ extern int class[LAST][LAST];
 #define	max(x,y)	(((x) >= (y)) ? (x) : (y))	/* beware of side effects */
 #define	min(x,y)	(((x) <= (y)) ? (x) : (y))
 
+#undef	sprintf	/* Snow Leopard */
+
 extern	char	errbuf[200];
 extern	char	*cmdname;
 #define	ERROR	sprintf(errbuf,

src/cmd/grap/grap.h

@@ -1,4 +1,7 @@
 extern	char	errbuf[200];
+
+#undef	sprintf	/* Snow Leopard */
+
 #define	ERROR	sprintf(errbuf,
 #define	FATAL	), yyerror(errbuf), exit(1)
 #define	WARNING	), yyerror(errbuf)

src/cmd/pic/pic.h

@@ -10,6 +10,9 @@
 extern	void	yyerror(char *);
 
 extern	char	errbuf[200];
+
+#undef	sprintf	/* Snow Leopard */
+
 #define	ERROR	sprintf(errbuf,
 #define	FATAL	), yyerror(errbuf), exit(1)
 #define	WARNING	), yyerror(errbuf)

src/cmd/tpic/pic.h

@@ -12,6 +12,9 @@
 #define	dprintf	if(dbg)printf
 
 extern	char	errbuf[200];
+
+#undef	sprintf	/* Snow Leopard */
+
 #define	ERROR	sprintf(errbuf,
 #define	FATAL	), yyerror(errbuf), exit(1)
 #define	WARNING	), yyerror(errbuf)

src/cmd/troff/tdef.h

@@ -68,6 +68,8 @@ typedef	struct	Tbuf	Tbuf;
 #define	oputs(a)	OUT "%s", a PUT
 #define	oput(c)		( *obufp++ = (c), obufp > obuf+BUFSIZ ? flusho() : 1 )
 
+#undef	sprintf	/* Snow Leopard */
+
 extern	char	errbuf[];
 #define	ERROR	sprintf(errbuf,
 #define	WARN	), errprint()

src/lib9/dirread.c

@@ -1,3 +1,7 @@
+#if defined(__APPLE__)
+#define _DARWIN_NO_64_BIT_INODE	/* Snow Leopard */
+#endif
+
 #include <u.h>
 #define NOPLAN9DEFINES
 #include <libc.h>

src/libthread/threadimpl.h

@@ -6,6 +6,9 @@
 #include <sched.h>
 #include <signal.h>
 #if !defined(__OpenBSD__)
+#	if defined(__APPLE__)
+#		define _XOPEN_SOURCE 	/* for Snow Leopard */
+#	endif
 #	include <ucontext.h>
 #endif
 #include <sys/utsname.h>