Provide basis for fixing lhash code

Provide basis for fixing lhash code

Following on from the earlier safestack work we provide the basis for
fixing the lhash code such that unused static inline functions do not
cause linker errors for applications including those headers.

This brings the lhash code into line with the safestack code.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12860)