gcc: Fix cygwin patches to be able build with _cxa_atexit
crypt: Fix doc folder
libtool: Rebuild for gc-4.9.2
msys2-runtime: Update to latest. Don't provide RPC headers. They will be in librpc
doxygen: Fix architectures. Rebuild.
libssh2: Rebuild
libxml2: Add new patch. Rebuild.
libxslt: Fix doc directory, dependencies. Rebuild.
icu: Rebuild.
curl: Update to 7.39.0