FirefoxOS: Can't build b2g for Emulator on Mac -Yosemite

Question

I am trying to build B2G on Mac - Yosemite (10.10.5)and I have a multiple version of Xcode 4.6.3,5.0.2, 6.4 and 7(beta 5). I follows the Mozilla Docs(https://developer.mozilla.org/en-US/docs/Mozilla/Firefox_OS/Preparing_for_your_first_B2G_build)

Terminal: (already installed autoconf (GNU Autoconf) 2.69)

1. Clone the Source Code : git clone git://github.com/mozilla-b2g/B2G.git
2. Commands run as per Mozilla doc : a. run ./config.sh emulator
   b. run ./build.sh -j1

After that I am getting this error :

host C++: aapt <= frameworks/base/tools/aapt/AaptAssets.cpp
couldn't understand kern.osversion `14.5.0'
In file included from frameworks/base/include/utils/Asset.h:24,
                 from frameworks/base/include/utils/AssetManager.h:23,
                 from frameworks/base/tools/aapt/AaptAssets.h:10,
                 from frameworks/base/tools/aapt/AaptAssets.cpp:5:
/usr/include/stdio.h:224:2: error: #error "_DARWIN_UNLIMITED_STREAMS specified, but -mmacosx-version-min version does not support it."
make: *** [out/host/darwin-x86/obj/EXECUTABLES/aapt_intermediates/AaptAssets.o] Error 1

real    0m47.189s
user    0m8.377s
sys 0m7.157s

> Build failed! <

Build with |./build.sh -j1| for better messages
If all else fails, use |rm -rf objdir-gecko| to clobber gecko and |rm -rf out| to clobber everything else.

For full console , go to : https://drive.google.com/open?id=0B8Xlqkz1LkRWdXh4S0VlaWNCZ1U and download, and Please give your suggestion.