No longer support DEBUG_CURLIO when libcwd isn't installed.
Merge remote-tracking branch 'singu/master'
This header uses LLMatrix4a, not LLMatrix4.
libcurl-gnutls.so (debian) links with libgnutls.so

In that case we DO reach the assert here.
I verified that curl_global_init() indeed calls gnutls_global_init().
Don't set a SSL ctx callback when we don't use openSSL.