CHECK_FUNCTION_EXISTS(vasprintf HAVE_VASPRINTF)
CHECK_FUNCTION_EXISTS(makecontext HAVE_MAKECONTEXT)
CHECK_FUNCTION_EXISTS(mmap HAVE_MMAP)
CHECK_FUNCTION_EXISTS(vasprintf HAVE_VASPRINTF)
CHECK_FUNCTION_EXISTS(makecontext HAVE_MAKECONTEXT)
CHECK_FUNCTION_EXISTS(mmap HAVE_MMAP)