when including the OpenSSL header files. This is the recommended setting, this
prevents the undesired inclusion of header files with the same name as those
of OpenSSL but which do not belong to the OpenSSL package. The visible change
from previously released libcurl versions is that now OpenSSl enabled NetWare
builds also define USE_OPENSSL in config files, and that OpenSSL header files
must be located in a subdirectory named 'openssl'.