convenience changes for cmake 4 and openmp on apple devices (#365)

Author: digitalillusions

CMake/Common.cmake

@@ -75,6 +75,10 @@ endif()
 
 option(USE_OpenMP "Use OpenMP" ON)
 if(USE_OpenMP)
+	# Add the default openmp installation directory for apple systems
+	if(APPLE)
+		set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH};/opt/homebrew/opt/libomp)
+	endif()
 	FIND_PACKAGE(OpenMP)
 	if(OPENMP_FOUND)
 		if (CMAKE_VERSION VERSION_GREATER "3.8")
@@ -83,6 +87,8 @@ if(USE_OpenMP)
 			SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
 			SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
 		endif()
+	else()
+		message("OpenMP could not be found. On Apple devices, make sure to install it with `brew install libomp`.")
 	endif()
 endif()