Use sort -u rather than echo grep sort.

diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index df5b9e509943f28d65607e1444c108332056fb95..12842f73673efe5adbfc0d052c92beab7c87df23 100644 (file)
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -1236,8 +1236,7 @@ trap '
 
     if test -s confdefs.h; then
       AS_BOX([confdefs.h.])
-      echo
-      grep . confdefs.h | sort
+      sort -u confdefs.h
       echo
     fi
     test "$ac_signal" != 0 &&