Resolve bug #6092.

Adds support on Mac OS X for both of compiler drivers "cc" and "c++"; only
"c++" worked previously.

Fixes stricmp/strnicmp issue for FreeBSD.

Thanks to John Utz <utz@singingfish.com> and Martin Redington <m.redington@ucl.ac.uk>.


git-svn-id: https://svn.apache.org/repos/asf/xerces/c/trunk@173505 13f79535-47bb-0310-9956-ffa450edef68