If the compiler dumps core, bash will print a useless error

message with the full path of the errchk script.  Catch that
by wrapping the if statement which invokes the compiler in a
subshell.  Use the $TMPOUT file as a flag to let the main
shell know whether the subshell ran.  Since the compiler
stdout and stderr are redirected, if the if statement produces
any output, then the compiler crashed, and we report that.

R=r,rsc
DELTA=14  (11 added, 1 deleted, 2 changed)
OCL=33690
CL=33692

test/errchk

@@ -34,11 +34,21 @@ rm -f $TMPOUT $TMPERR $TMPALL $TMPTMP $TMPBUG
 
 trap "rm -f $TMPOUT $TMPERR $TMPALL $TMPTMP $TMPBUG" 0 1 2 3 14 15
 
-if $* >$TMPOUT 2>$TMPERR; then
-  echo 1>&2 "BUG: errchk: command succeeded unexpectedly"
+(if $* >$TMPOUT 2>$TMPERR; then
+   echo 1>&4 "BUG: errchk: command succeeded unexpectedly"
+   cat 1>&3 $TMPOUT
+   cat 1>&4 $TMPERR
+   rm -f $TMPOUT $TMPERR
+ fi) 3>&1 4>&2 >$TMPTMP 2>&1
+
+if ! test -f $TMPOUT; then
+  exit 0
+fi
+
+if test -s $TMPTMP; then
+  echo 1>&2 BUG: errchk: compiler crashed
   cat $TMPOUT
   cat 1>&2 $TMPERR
-  rm -f $TMPOUT $TMPERR
   exit 0
 fi