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.
Move CMAKE_USE_OPENSSL and CURL_CA_BUNDLE up to the top of CMake so that
CMake's own sources can know their values. Add the CURL_CA_PATH option
at the top and honor it as part of the curl build.
Re-apply the logic change made by commit v2.8.2~536 (Use arch-aware
CHECK_TYPE_SIZE result, 2009-12-17). The size of some types must be
selected at preprocessing time when building for multiple archs on OS X.