Fixes issues that occur when building on Apple Silicon (#88)

Add .dylib option when building on MacOS
Disabled use of -march=native when on Apple Silicon
Link to CppInterOp (without this on MacOS you get undefined symbols error when building). Pick CppInterOp library file extension without hardcoding

CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.10)
 
 project(cppyy-backend)
 include(ExternalProject)
+include(CMakeSystemSpecificInformation)
 
 set(CMAKE_FIND_PACKAGE_SORT_ORDER NATURAL)
 set(CMAKE_FIND_PACKAGE_SORT_DIRECTION DEC)
@@ -64,4 +65,8 @@ endif()
 set_source_files_properties(clingwrapper/src/clingwrapper.cxx
   PROPERTIES COMPILE_DEFINITIONS "CPPINTEROP_DIR=\"${_interop_install_dir}\"")
 
+# Link to CppInterOp library. Without this can't build on MacOS due to undefined symbols
+target_link_libraries(cppyy-backend ${_interop_install_dir}/lib/libclangCppInterOp${CMAKE_SHARED_LIBRARY_SUFFIX})
+
+
 target_include_directories(cppyy-backend PUBLIC ${_interop_install_dir}/include)

clingwrapper/setup.py

@@ -24,8 +24,10 @@
 
 if 'win32' in sys.platform:
     soext = '.dll'
-else:
+elif 'linux' in sys.platform:
     soext = '.so'
+else:
+    soext = '.dylib'
 
 #
 # platform-dependent helpers

clingwrapper/src/clingwrapper.cxx

@@ -171,11 +171,32 @@ class ApplicationStarter {
             Interp = existingInterp;
         }
         else {
+#ifdef __arm64__
+#ifdef __APPLE__
+            // If on apple silicon don't use -march=native
+            std::vector<const char *> InterpArgs({"-std=c++17"});
+#else
+            std::vector<const char *> InterpArgs(
+                {"-std=c++17", "-march=native"});
+#endif
+#else
             std::vector <const char *> InterpArgs({"-std=c++17", "-march=native"});
+#endif
             char *InterpArgString = getenv("CPPINTEROP_EXTRA_INTERPRETER_ARGS");
+
             if (InterpArgString)
-               push_tokens_from_string(InterpArgString, InterpArgs);
+              push_tokens_from_string(InterpArgString, InterpArgs);
+
+#ifdef __arm64__
+#ifdef __APPLE__
+            // If on apple silicon don't use -march=native
+            Interp = Cpp::CreateInterpreter({"-std=c++17"});
+#else
             Interp = Cpp::CreateInterpreter({"-std=c++17", "-march=native"});
+#endif
+#else
+            Interp = Cpp::CreateInterpreter({"-std=c++17", "-march=native"});
+#endif
         }
 
         // fill out the builtins

python/cppyy_backend/loader.py

@@ -19,8 +19,10 @@
 
 if 'win32' in sys.platform:
     soext = '.dll'
-else:
+elif 'linux' in sys.platform:
     soext = '.so'
+else:
+    soext = '.dylib'
 
 soabi = sysconfig.get_config_var("SOABI")
 soext2 = sysconfig.get_config_var("EXT_SUFFIX")