Record compile features for GNU on Apple.

Tested with GNU 4.8 binary (bottle) from homebrew, and assumed to work
with the others.

Modules/Compiler/GNU-C.cmake

@@ -23,7 +23,7 @@ macro(cmake_record_c_compile_features)
     record_compiler_features(C "${std_version}" ${list})
   endmacro()
 
-  if (UNIX AND NOT APPLE AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
+  if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
     _get_gcc_features(${CMAKE_C11_STANDARD_COMPILE_OPTION} CMAKE_C11_COMPILE_FEATURES)
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_C99_STANDARD_COMPILE_OPTION} CMAKE_C99_COMPILE_FEATURES)

Modules/Compiler/GNU-CXX.cmake

@@ -39,10 +39,10 @@ macro(cmake_record_cxx_compile_features)
   endmacro()
 
   set(_result 0)
-  if (UNIX AND NOT APPLE AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
+  if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
     _get_gcc_features(${CMAKE_CXX14_STANDARD_COMPILE_OPTION} CMAKE_CXX14_COMPILE_FEATURES)
   endif()
-  if (UNIX AND NOT APPLE AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+  if (UNIX AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
     if (_result EQUAL 0)
       _get_gcc_features(${CMAKE_CXX11_STANDARD_COMPILE_OPTION} CMAKE_CXX11_COMPILE_FEATURES)
     endif()