* configure.ac: Adjust to call...
    * m4/intel.m4: ...this new macro.
    * Makefile.am: Add the directory `m4' as an includedir of
    autoconf's macros.

    * m4/intel.m4: Remove the `-W' option from CXXFLAGS since icpc
    does not support it. Inhibit the warning ``method was declared
    but never referenced''.