message: Better matching to detect Clang in Apple
  The name is actually AppleClang, not just Clang.
diff: @@ -24,8 +24,7 @@ target_include_directories(
  PUBLIC .)
  target_link_libraries(${LIBRARY_NAME} PUBLIC xacc CppMicroServices PRIVATE xacc-pauli)
  -
  -if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
  +if (CMAKE_CXX_COMPILER_ID MATCHES "^(Apple)?Clang$")
  include(CheckSymbolExists)
  # Check for function std::beta
  check_cxx_symbol_exists(std::beta "cmath" HAVE_STD_BETA)
  