Specifically:
- Enable C++, Fortran 77 and Fortran (95+) through Libtool's LT_LANG
if available and through the traditional AC_PROG_* macros if not.
This configuration is compatible with the versions of Libtool
easily available for testing. For whatever reason--possibly a
programming error in Libtool proper--invoking the AC_PROG_F*
macros either directly or through AC_REQUIRE following an LT_INIT
invocation leads to various ``expanded before required'' warnings.
Searching the Autotools mailing lists does suggest that the
interaction of C++, Fortran and Libtool is traditionally somewhat
unstable but has improved in very recent editions of Autoconf and
Libtool.
- Re-factor the LAPACK support out to a custom macro, OPM_LAPACK,
and invoke it from configure.ac.
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