Allow to build shared libraries if BUILD_SHARED_LIBS is enabled

Contributed-by: Richard Membarth <richard.membarth@uni-saarland.de>

git-svn-id: https://llvm.org/svn/llvm-project/polly/branches/release_36@231275 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed