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.
Set curl build options as needed for CMake rather than presenting them
to the user in the cache. Drop the CMAKE_BUILD_CURL_SHARED option for
now.
Change the curl library name to 'cmcurl'. Disable blocks of code within
curl CMakeLists.txt files that we do not need for CMake, but leave the
code in place to make merging with curl updates easier.
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.
The resource file is only needed for the curl .dll, so skip it when
building the static library. This avoids the need to add the
'/machine:' link flag on MS tools for creating a static library.