Support for split LLVM libs (#230)

Support for split LLVM libs

Support for split LLVM libs is added since Gentoo does not distribute a
combined LLVM library.

src/ast/CMakeLists.txt

@@ -36,5 +36,14 @@ if (STATIC_LINKING)
   target_link_libraries(ast ${clang_libs})
   target_link_libraries(ast ${llvm_libs})
 else()
-  target_link_libraries(ast LLVM libclang)
+  find_library(found_LLVM LLVM)
+  if(found_LLVM)
+    target_link_libraries(ast LLVM)
+  else()
+    llvm_map_components_to_libnames(_llvm_libs bpfcodegen ipo irreader mcjit orcjit ${LLVM_TARGETS_TO_BUILD})
+    llvm_expand_dependencies(llvm_libs ${_llvm_libs})
+    target_link_libraries(ast ${llvm_libs})
+  endif()
+
+  target_link_libraries(ast libclang)
 endif()