Regression tests for gm2 in the repository

The regression testsuite can be run from the gcc build directory:

$ cd build-gcc
$ make check -j 24

which runs the complete testsuite for all compilers using 24 parallel invocations of the compiler. Individual language testsuites can be run by specifying the language, for example the Modula-2 testsuite can be run using:

$ cd build-gcc
$ make check-m2 -j 24

Finally the results of the testsuite can be emailed to the gcc-testresults list using the script:

$ gccsrcdir/contrib/test_summary