PROTON-657: Fix build to use detected include directory for OpenSSL

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1622404 13f79535-47bb-0310-9956-ffa450edef68
PROTON-660: Fix openssl.c build on windows

For macro issues, use workaround from http://rt.openssl.org/Ticket/Display.html?id=3031
replace strcasecmp with !pn_i_eq_nocase
replace strncasecmp with !pn_i_eq_n_nocase