With XCode 11 there is no more /usr/include directory. This
does not affect the XCode compilers, but does make goma compiler
break. This finds the system includes the same way that the iOS
builds currently do.
The gn_to_bp.py tool runs gn with target_os == mac, but host_os != mac.
In that case, the xcrun tool can not run, so make xcode_sysroot = "". This will
allow the xcode compilers to work when using the android.bp to build things.
TESTED:
builds on mac with and without goma
Change-Id: I9de6797c32760c59e62fe5ac505a3404e5eaf8e9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249537
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
