build: compile with -D__DARWIN_64_BIT_INO_T on OS X

Fixes a struct stat size mismatch on 64 bits machines that made Node crash with
a EXC_BAD_ACCESS on startup.

Solution proposed by Paddy Byers.

config-unix.mk

@@ -50,6 +50,7 @@ endif
 ifeq (Darwin,$(uname_S))
 EV_CONFIG=config_darwin.h
 EIO_CONFIG=config_darwin.h
+CPPFLAGS += -D__DARWIN_64_BIT_INO_T=1
 CPPFLAGS += -Isrc/ares/config_darwin
 LINKFLAGS+=-framework CoreServices
 OBJS += src/unix/darwin.o

uv.gyp

@@ -9,6 +9,9 @@
           'EIO_STACKSIZE=262144'
         ],
         'conditions': [
+          ['OS=="mac"', {
+            'defines': ['__DARWIN_64_BIT_INO_T=1'],
+          }],
           ['OS=="solaris"', {
             'cflags': ['-pthreads'],
             'ldlags': ['-pthreads'],