git: allow to set NO_APPLE_COMMON_CRYPTO=1

[certik]

This fixes a build failure on OS X 10.10. Unfortunately, this disabled https
access, so it is only enabled if 'disable_crypto' parameter is 'true'.

[certik]

I should note that git builds fine with the native clang, but fails with gcc. So a profile with clang doesn't need any parameter, but a profile with gcc requires disable_crypto: true. But since it disables the https access, it's not an ideal solution at all, rather a workaround to get git build at all. We need to find a better solution for this.

[jcftang]

+1

[certik]

Thanks. By default it doesn't do anything, and it optionally allows to make git build on OS X with gcc, albeit not ideally. We can improve upon this later.