Rip out Xcode hack to fix build under OSX. Users should just upgrade their version of CMake (3.2.3 seems fine) to fix the performance issues that this hack tried to address.
Rip out Xcode hack to fix build under OSX. Users should just upgrade
their version of CMake (3.2.3 seems fine) to fix the performance issues
that this hack tried to address.

This hack was incompatible with recent changes because the LLVM
libraries need to be passed to ``target_link_libraries(Halide PUBLIC
...)``.

The performance issue seems to have been reported on CMake's bug tracker
[1] and has been fixed in the new versions of CMake.

[1] https://public.kitware.com/Bug/bug_relationship_graph.php?bug_id=15178&graph=dependency


Former-commit-id: 7278eec9f51f50396165cf1b445382ef9a388028
darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide