Resolve conflicts by taking upstream side when possible and otherwise
integrating the changes from both sides. Be carful in CMakeLists.txt
where the OPENSSL code block that we modified previously has moved, and
preserve our previous modifications in the new location.
Use a CMake-specific path to this configured header so that it works
when included from a CMake source file in addition to curl sources.
We do not install the Curl headers with CMake, so this hack is okay.
Re-apply change from commit v2.8.0~1683 (add initial support for HAIKU
OS, 2008-09-15) on updated upstream curl. However, leave out the part
that was reverted by commit v3.0.0-rc1~541^2~1 (Haiku: Remove outdated
preprocessor checks, 2013-10-05).
Brad King