When compiling with -Wall g77 marks all variables passed through
COMMON as unused.  This practically nullifies a usefulness of this
warning.  Attached sample program when compiled with g77 from 6.2
distribution (egcs) produces the following:

mdbnch2.f: In subroutine `minit':
mdbnch2.f:315: warning: unused variable `cf'
mdbnch2.f: In subroutine `mstep':
mdbnch2.f:881: warning: unused variable `chart'
mdbnch2.f:881: warning: unused variable `chars'
mdbnch2.f:881: warning: unused variable `chard'
mdbnch2.f: In subroutine `crystl':
mdbnch2.f:1978: warning: unused variable `name'

which is correct.  A new version of compiler generates close to 960
"unused variable" warnings on the same source.

  Michal
  michal