- Trailer function support.
- http 0.9 option.
- curl_easy_upkeep.

The DCL code had a typo in one of the commands which would make the
OpenSSL discovery on VAX fail. The correct syntax is F$ENVIRONMENT.

Closes #3407
Reviewed-by: Viktor Szakats <commit@vszakats.net>

Curl_slist_append_nodup() returns NULL when it fails to create a new
item for the specified list, and since the coding here reassigned the
new list on top of the old list it would result in a dangling pointer
and lost memory. Also, in case we hit an allocation failure at some
point during the conversion, with allocation succeeding again on the
subsequent call(s) we will return a truncated list around the malloc
failure point. Fix by assigning to a temporary list pointer, which can
be checked (which is the common pattern for slist appending), and free
all the resources on allocation failure.

Closes #3372
Reviewed-by: Daniel Stenberg <daniel@haxx.se>

This subdir has mostly become an attic of never-used cruft from the
past.

Closes #3331

Closes #3291

Commit 709cf76f6bb7dbac deprecated USE_SSLEAY, as curl since long isn't
compatible with the SSLeay library. This removes the few leftovers that
were omitted in the less frequently used platform targets.

Closes #3270
Reviewed-by: Daniel Stenberg <daniel@haxx.se>