reorganize octave_config_info again * build-env-features.sh: Don't include ENABLE_ items in the output. * toplev.cc (find_config_info): New static function. (Foctave_config_info): Put Octave configuration info in the main struct. Put the build system features and build environment info in substructures. Allow searching of all elements by keyword. * __have_feature__.m, doc/interpreter/testfun.txi: Fix name of build features substructure element. * geometryimages.m, interpimages.m, plotimages.m, sparseimages.m, splineimages.m: Use __have_feature__ to check for OSMESA.

gnulib-hg = gnulib-hg