Use add_llvm_loadable_module

Can't get ordinary CMake add_library to work for whatever reason.

CMakeLists.txt

 find_package(LLVM REQUIRED CONFIG)
 
+list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
+include(AddLLVM)
+
 add_definitions(${LLVM_DEFINITIONS})
 include_directories(${LLVM_INCLUDE_DIRS})
 

skeleton/CMakeLists.txt

-add_library(SkeletonPass MODULE Skeleton.cpp)
+add_llvm_loadable_module(SkeletonPass
+    # List your source files here.
+    Skeleton.cpp
+)