(not (yet?) an end-user option in the build system)
(If extended to build system, build system should also unset CRYPTO_LIB)
If WITHOUT_LIB_CRYPTO is defined in sys-crypto.h, then non-TLS modules
will have access to MD5() and SHA1() built with lighttpd (algo_md5.[ch]
and algo_sha1.[ch]), but not to other message digest algorithms.
As of this commit, this affects only mod_secdownload with SHA256 digest
and mod_auth* modules using HTTP Digest Auth with digest=SHA-256, which
is not currently well-supported by client browers (besides Opera)