curl_multi_fdset.3: improved the formatting slightly
Cmake: Check for OpenSSL before OpenLDAP.

OpenLDAP might have been build with OpenSSL. Checking for OpenLDAP first
may result in undefined symbols. Of course, the found OpenSSL libraries
must also be linked whenever OpenLDAP is.
Cmake: Fix library list provided to cURL tests.

The list must be set after those nice CMake tests as we mess with
CMAKE_REQUIRED_LIBRARIES there.
Cmake: Avoid cycle directory dependencies.

Because we prepended libraries to list, CMake had troubles resolving
link directory order as it detected some cycles. Appending to list ensures
that dependencies will preceed dependees.
Cmake: Got rid of setup_curl_dependencies

There is no need for such function. Include_directories propagate by
themselves and having a function with one simple link statement makes
little sense.
Cmake: Build with GSSAPI (MIT or Heimdal)

It tries hard to recognise SDK's on different platforms. On windows MIT
Kerberos installs SDK with other things and puts path into registry.
Heimdal have separate zip archive. On linux pkg-config is tried, then
krb5-config script and finally old-style libs and headers detection.

Command line args:
* CMAKE_USE_GSSAPI - enables GSSAPI detection
* GSS_ROOT_DIR - if set, should point to the root of GSSAPI installation
                 (the one with include and lib directories)