ran into some issues with the GSSAPI tests in configure.ac. The tests first
  try to determine the include dirs and libs and set CPPFLAGS and LIBS
  accordingly. It then checks for the headers and finally sets LIBS a second
  time, causing the libs to be included twice. The first setting of LIBS seems
  redundant and should be left out, since the first part is otherwise just
  about finding headers.

  My second issue is that 'krb5-config --libs gssapi' on Darwin is less than
  useless and returns junk that, while it happens to work with gcc, causes
  clang to choke. For example, --libs returns $CFLAGS along with the libs,
  which is really retarded. Simply setting 'LIBS="$LIBS -lgssapi_krb5
  -lresolv"' on Darwin is sufficient.