But I suspect its no longer possible since it appears to require a more recent version of XCode - error in one function due to 'forced copy in constructor'. It was related to a parents = {} parameter, I didn't dig too deeply.
Not to worry, it gave me a good reason to upgrade to El Capitan.
[carpii@imac:~/dev/textmate]$ clang++ --version
Apple LLVM version 7.3.0 (clang-703.0.31)
Target: x86_64-apple-darwin15.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
[carpii@imac:~/dev/textmate]$ clang --version
Apple LLVM version 7.3.0 (clang-703.0.31)
Target: x86_64-apple-darwin15.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
[carpii@imac:~/dev/textmate]$ xcodebuild -version
Xcode 7.3.1
Build version 7D1014
[carpii@imac:~/dev/textmate]$ sw_vers -productVersion
10.11.5
------- compilation
[carpii@imac:~/dev/textmate]$ ninja -t clean
Cleaning... 515 files.
[carpii@imac:~/dev/textmate]$ ninja io
[1/1] Generate ‘build.ninja’…
[109/109] Run test ‘/Users/carpii/build/TextMate/Frameworks/io/test_io’…
[carpii@imac:~/dev/textmate]$ ninja TextMate
[229/1107] Run test ‘/Users/carpii/build/TextMate/Frameworks/scm/test_scm’…
FAILED: /Users/carpii/build/TextMate/Frameworks/scm/test_scm && touch /Users/carpii/build/TextMate/Frameworks/scm/test_scm.run
/bin/sh: line 1: 7210 Segmentation fault: 11 /Users/carpii/build/TextMate/Frameworks/scm/test_scm
[229/1107] Compile ‘Frameworks/file/src/open.cc’…
ninja: build stopped: subcommand failed.