Move some macros from include/openssl/opensslconf.h.in, add OPENSSL_FUNC

Move some macros from include/openssl/opensslconf.h.in, add OPENSSL_FUNC

New header file, include/openssl/macros.h, which contains diverse
useful macros that we use elsewhere.

We also add the new macro OPENSSL_FUNC, which is an alias for
__FUNC__, __FUNCTION__, __FUNCSIG or __func__, depending on what the
compiler supports.  In the worst case, it's an alias for the string
"(unknown function)".

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9452)