Haiku specific fix: add major and minor defines if they aren't there.

Signed-off-by: Brian Ford <bford@engineyard.com>

vm/ffi_util.cpp

@@ -152,6 +152,14 @@ unsigned int ffi_cast(unsigned int val) {
   return val;
 }
 
+#ifndef major
+#define major(x) x
+#endif
+
+#ifndef minor
+#define minor(x) 0
+#endif
+
 long ffi_major(dev_t n) {
   return major(n);
 }