(svn r11541) -Fix: [OSX] detect statvfs at runtime (based on OSX version) instead of compile time

This should prevent a crash on OSX 10.3 with the precompiled binaries (in the load/save windows)

src/unix.cpp

@@ -67,6 +67,10 @@ bool FiosGetDiskFreeSpace(const char *path, uint32 *tot)
 	uint32 free = 0;
 
 #ifdef HAS_STATVFS
+# ifdef __APPLE__
+	/* OSX 10.3 lacks statvfs so don't try to use it even though later versions of OSX has it. */
+	if (MacOSVersionIsAtLeast(10, 4, 0))
+# endif
 	{
 		struct statvfs s;