I guess that's the reason for
https://github.com/yonaskolb/XcodeGen/issues/51#issuecomment-381216565,
I haven't modified original pull request after new discoveries found in
discussion #283 (primarily - that it is not Xcode 9.3 issue, but issue
caused by Xcode and CLT installed in the same time).
This patch modifies ENV only if CLT is installed.
I've checked it against Xcode + CLT and it worked fine, it'll be great
if someone can confirm that this one works on Xcode only system. You
can do that by running `brew edit xcodegen` and after patching
`brew reinstall xcodegen`
`libxml2` has to be included in `ISYSTEM_PATH` for building one of
dependencies. It didn't happen automatically before Xcode 9.3
so `homebrew` patched environment variable to get it work.
But since Xcode 9.3 includes it already, the build will fail
because of redefinition of `libxml2` module.
It's a bug of `homebrew` but before it's fixed, it's easier
to provide in-place workaround for now.
Fixes#283
* [homebrew] Add formula
* [homebrew] Update README.md to include the steps to install it using Homebrew
* [homebrew] Fix formula
* [homebrew] Add test method
* [homebrew] Update formula version
* [homebrew] Fix formula