Silence some Mac OS X warnings.

bin/9c

@@ -11,6 +11,7 @@ usegcc()
 		-Wno-parentheses \
 		-Wno-missing-braces \
 		-Wno-switch \
+		-Wno-sign-compare \
 	"
 }
 

src/lib9/dirwstat.c

@@ -10,7 +10,7 @@ dirwstat(char *file, Dir *dir)
 	struct utimbuf ub;
 
 	/* BUG handle more */
-	if(dir->mtime == ~0ULL)
+	if(~dir->mtime == 0)
 		return 0;
 
 	ub.actime = dir->mtime;

src/lib9/ffork-pthread.c

@@ -7,7 +7,6 @@ extern int __isthreaded;
 int
 ffork(int flags, void(*fn)(void*), void *arg)
 {
-	void *p;
 	pthread_t tid;
 
 	if(flags != (RFMEM|RFNOWAIT)){

src/libfmt/nan64.c

@@ -7,6 +7,10 @@
 
 #include "nan.h"
 
+#ifdef __APPLE__
+#define _NEEDLL
+#endif
+
 typedef unsigned long long uvlong;
 typedef unsigned long ulong;
 

src/libthread/PowerMacintosh.c

@@ -12,7 +12,6 @@ void
 _threadinitstack(Thread *t, void (*f)(void*), void *arg)
 {
 	ulong *tos, *stk;
-	int n;
 
 	tos = (ulong*)&t->stk[t->stksize&~7];
 	stk = tos;