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 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.
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that was reverted by commit v3.0.0-rc1~541^2~1 (Haiku: Remove outdated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).
We imported curl from an upstream release, so report the corresponding
release version to servers. This is consistent with the version we
presented when our builtin curl was 7.16.1.
Brad King