Non apple clang also does not support march native on arm64; add output for trycompile if it fails

CMakeLists.txt

@@ -365,7 +365,7 @@ endif()
 # architecture optimization
 if( WALBERLA_OPTIMIZE_FOR_LOCALHOST )
    if( WALBERLA_CXX_COMPILER_IS_GNU OR WALBERLA_CXX_COMPILER_IS_INTEL OR WALBERLA_CXX_COMPILER_IS_CLANG )
-      if( CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "arm64" )
+      if(( CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang" ) AND CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "arm64" )
         # no -march=native available on this compiler, but there is currently only one such processor
       else()
         add_flag ( CMAKE_CXX_FLAGS "-march=native" )
@@ -487,7 +487,7 @@ endif()
 ############################################################################################################################
 
 try_compile( WALBERLA_USE_STD_FILESYSTEM "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/cmake/TestStdFilesystem.cpp"
-             COMPILE_DEFINITIONS -DWALBERLA_USE_STD_FILESYSTEM COPY_FILE "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" )
+      COMPILE_DEFINITIONS -DWALBERLA_USE_STD_FILESYSTEM COPY_FILE "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" OUTPUT_VARIABLE TRY_COMPILE_OUTPUT)
 if( WALBERLA_USE_STD_FILESYSTEM )
   # detect https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90050 by checking whether it segfaults
   execute_process( COMMAND "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" OUTPUT_QUIET RESULT_VARIABLE WALBERLA_STD_FILESYSTEM_WORKS )
@@ -496,14 +496,14 @@ if( WALBERLA_USE_STD_FILESYSTEM AND WALBERLA_STD_FILESYSTEM_WORKS EQUAL 0 )
    message( STATUS "Found std::filesystem")
 else()
    try_compile( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/cmake/TestStdFilesystem.cpp"
-                COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
+         COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM OUTPUT_VARIABLE TRY_COMPILE_OUTPUT)
    if( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
       message( STATUS "Found std::experimental::filesystem")
    endif()
    if( NOT WALBERLA_CXX_COMPILER_IS_MSVC AND NOT WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
       unset( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM CACHE )
       try_compile( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/cmake/TestStdFilesystem.cpp"
-                   COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM LINK_LIBRARIES stdc++fs )
+            COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM LINK_LIBRARIES stdc++fs OUTPUT_VARIABLE TRY_COMPILE_OUTPUT)
       if( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
          message( STATUS "Found std::experimental::filesystem in libstdc++fs")
       list ( APPEND SERVICE_LIBS -lstdc++fs )
@@ -512,14 +512,15 @@ else()
    if( NOT WALBERLA_CXX_COMPILER_IS_MSVC AND NOT WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
       unset( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM CACHE )
       try_compile( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}/cmake/TestStdFilesystem.cpp"
-                   COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM LINK_LIBRARIES c++experimental )
+            COMPILE_DEFINITIONS -DWALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM LINK_LIBRARIES c++experimental OUTPUT_VARIABLE TRY_COMPILE_OUTPUT)
       if( WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM )
          message( STATUS "Found std::experimental::filesystem in libc++experimental")
          list ( APPEND SERVICE_LIBS -lc++experimental )
       endif()
    endif()
    if( NOT WALBERLA_USE_STD_EXPERIMENTAL_FILESYSTEM AND NOT WALBERLA_USE_STD_FILESYSTEM)
-       message(FATAL_ERROR "Neither std::filesystem nor std::experimental::filesystem are available")
+      message( WARNING ${TRY_COMPILE_OUTPUT} )
+      message( FATAL_ERROR "Neither std::filesystem nor std::experimental::filesystem are available" )
    endif()
 endif()