When compiling using -fsanitize=thread in GCC 7.3.0, a compilation
error occurs because GCC 7.3.0 does not support the "no_sanitize"
attribute. The current usages of the "no_sanitize" attribute when
compiling with -fsanitize=thread are "undefined" and
"nonnull-attribute". These can be replaced with the
"no_sanitize_undefined" and "nonnull" attributes respectively.

Do some feature checking to see if the appropriate attributes are
supported, and use them, or an alternative, if they are.

__has_cpp_attribute.

Provide explicit error messages if required attributes were not
found.