Refactor all ISL-related cmake build instructions into its own
CMakeLists.txt and build as a separate library.
This is useful to apply ISL-related build flags to ISL only and not to
Polly's files. Also, it the separation of both projects becomes clearer.
Proposed name of the library is Polly_isl. It is not "isl" to avoid
mix-up with potentially installed libisl.{a|so}.
Tested configurations:
- Windows with cmake 3.2
- Ubuntu with cmake 3.0.2
- Ubuntu with cmake 3.0.2 BUILD_SHARED_LIBS on
- Ubuntu with cmake 2.8.12.2 (LLVM minimum version)
- Ubuntu out-of-LLVM-tree
Differential Revision: http://reviews.llvm.org/D12810
llvm-svn: 248484
519b3cfd27