For the 20000 or so regressiontests do larger diff using

cmp as on many systems multiple differences affecting
many tests will be painfully slow.  Affects
tests generating text over 30MB (some individual
tests generate 3GB to 5GB of text)..
	modified:   scripts/run-all-tests.sh

scripts/run-all-tests.sh

@@ -181,8 +181,11 @@ runfullddtest() {
   cd $ddtestdir
   chkres $? "H FAIL: cd $ddtestdir failed , giving up."
 
+  # so big diff files just do cmp
+  export SUPPRESSBIGDIFFS=y
   $rtestsrc/INITIALSETUP.sh $rtestsrc  
   chkres $? "J FAIL  INITIALSETUP failed $ddtestdir. giving up."
+  unset SUPPRESSBIGDIFFS
 
   $rtestsrc/RUNALL.sh
   chkres $? "J FAIL  RUNALL failed $ddtestdir."