unable to install homebrew
From your output, it looks like the developer tools version of git is missing. You could uninstall Xcode (delete it) and try again a manual install of just the tools homebrew needs.

I prefer to install the command line tools as follows:


Have an admin user/password handy - you don't need to be logged in as an admin - just know the password
/usr/bin/xcode-select --install


That should either error if you have Xcode already installed or command line tools. If you don't have the necessary tools - it will download and ask for installation.

Please note - the Mac App store is having issues right now - you might be doing everything right and need to wait for the server issues to get sorted:


http://www.apple.com/support/systemstatus/




To get past the check you are running into, the command below needs to return a good match that git is Mach-O 64-bit executable x86_64:

file $(/usr/bin/xcode-select -print-path)/usr/bin/git