check printf format strings

R=r
DELTA=18  (16 added, 0 deleted, 2 changed)
OCL=21177
CL=21185

src/runtime/Makefile

@@ -54,10 +54,10 @@ clean:
 	rm -f *.$(O) *.a runtime.acid
 
 %.$O:	%.c
-	$(CC) -w $<
+	$(CC) -wF $<
 
 sys_file.$O:	sys_file.c sys_types.h $(OS_H)
-	$(CC) -w -D$(GOARCH)_$(GOOS) $<
+	$(CC) -wF -D$(GOARCH)_$(GOOS) $<
 
 %.$O:	%.s
 	$(AS) $<

src/runtime/runtime.h

@@ -281,6 +281,22 @@ int32	funcline(Func*, uint64);
 void*	stackalloc(uint32);
 void	stackfree(void*);
 
+#pragma	varargck	argpos	printf	1
+
+#pragma	varargck	type	"d"	int32
+#pragma	varargck	type	"d"	uint32
+#pragma	varargck	type	"D"	int64
+#pragma	varargck	type	"D"	uint64
+#pragma	varargck	type	"x"	int32
+#pragma	varargck	type	"x"	uint32
+#pragma	varargck	type	"X"	int64
+#pragma	varargck	type	"X"	uint64
+#pragma	varargck	type	"p"	void*
+#pragma	varargck	type	"p"	uint64
+#pragma	varargck	type	"s"	int8*
+#pragma	varargck	type	"s"	uint8*
+#pragma	varargck	type	"S"	string
+
 // TODO(rsc): Remove. These are only temporary,
 // for the mark and sweep collector.
 void	stoptheworld(void);