A `-DBUILD_SHARED_LIBS=ON` build on Solaris/amd64 failed with
Undefined first referenced
symbol in file
_ZNK4llvm3cfg6UpdateIPNS_10BasicBlockEE4dumpEv tools/polly/unittests/DeLICM/CMakeFiles/DeLICMTests.dir/DeLICMTest.cpp.o (symbol belongs to implicit dependency /var/llvm/local-amd64-release-stage2-shared-A/bin/../lib/libLLVMCore.so.14git)
ld: fatal: symbol referencing errors
Solaris `ld` requires to directly link with dependant libraries, so this
patch explicitly adds `libLLVMCore`.
Tested on `amd64-pc-solaris2.11` and `x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D118452