FEAT: add a try_output_compile in numpy.distutils.
FEAT: add check_gcc_function_attribute check.
FEAT: add check to ensure compilation without warning for a piece of code.
ENH: don't use check_func anymore for check_compile_without_warning.
BUG: fix check_gcc_function_attribute when attribute is actually supported.
ENH: use pragma instead of generic warning when detecting for function attributes.
FEAT: add a check_gcc_variable_attribute function in config command.
REF: remove obsolete code.
Merge pull request #4842 from cournape/fix_intrinsics_detection

fix unknown attribute warnings under clang