change C99 comment to C89 comment
corrected reference output for bug818 and bug892
correct reference output for "hang" test

this test no longer hangs
minor makefile cleanups

- check_PROGRAMS, CLEANFILES, and TESTS are common to all test-makefiles,
  so we put them into testprog.am
- Makefile does not directly depend on Makefile.am, but Makefile.in does