Solaris does not support the gssapi library option to krb5-config, however
it does have a gssapi implementation.  Requiring us to look for the library
in a well known path.

This is being put on a branch since trunk no longer has gssapi detection
support since it has been moved into serf.

* build/ac-macros/gssapi.m4:
  (SVN_LIB_RA_SERF_GSSAPI): Detect when krb5-config --libs gssapi fails and
    try with krb5-config --libs krb5 and then use -lgss and
    -I/usr/include/gssapi.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-gssapi-solaris10@1453166 13f79535-47bb-0310-9956-ffa450edef68