More changes to 32/64 bit correctness.

src/utils.h

Index: src/utils.h
===================================================================
--- src/utils.h	(revision 5543)
+++ src/utils.h	(working copy)
@@ -224,16 +224,18 @@
 
 #if __GNUC__ >= 4
 // On gcc we can ask the compiler to check the types of %d-style format
-// specifiers and their associated arguments.
+// specifiers and their associated arguments.  TODO(erikcorry) fix this
+// so it works on MacOSX.
+#if defined(__MACH__) && defined(__APPLE__)
+#define PRINTF_CHECKING
+#else  // MacOsX.
 #define PRINTF_CHECKING __attribute__ ((format (printf, 1, 2)))
+#endif
 #else
 #define PRINTF_CHECKING
 #endif
 
-// Our version of printf(). Avoids compilation errors that we get
-// with standard printf when attempting to print pointers, etc.
-// (the errors are due to the extra compilation flags, which we
-// want elsewhere).
+// Our version of printf().
 void PRINTF_CHECKING PrintF(const char* format, ...);
 
 // Our version of fflush.