[Polly] Support linking ScopPassManager against LLVM dylib

Link ScopPassManager to LLVM dylib target if LLVM_LINK_LLVM_DYLIB
is enabled.  This fixes build failures on systems where static LLVM
libraries are not installed.

Differential Revision: https://reviews.llvm.org/D85281

Author: mgorny

polly/unittests/ScopPassManager/CMakeLists.txt

@@ -1,5 +1,7 @@
-llvm_map_components_to_libnames(llvm_libs Passes Core Analysis)
 add_polly_unittest(ScopPassManagerTests
   PassManagerTest.cpp
   )
-target_link_libraries(ScopPassManagerTests PRIVATE ${llvm_libs})
+if (NOT LLVM_LINK_LLVM_DYLIB)
+  llvm_map_components_to_libnames(llvm_libs Passes Core Analysis)
+  target_link_libraries(ScopPassManagerTests PRIVATE ${llvm_libs})
+endif()