Index: ccdep.pl
===================================================================
--- ccdep.pl	(revision 123)
+++ ccdep.pl	(revision 125)
@@ -137,13 +137,20 @@
 
 my @DS=find_ds();
 my @DSQ=map{shq$_}@DS;
-my $R="$GCCP -DOBJDEP -M -MG -E 2>&1 @DSQ";
-$R=backtick($R);
+my $DIAG=" -fno-diagnostics-show-caret";
+my $Q="$GCCP -DOBJDEP$DIAG -M -MG -E 2>&1 @DSQ";
+my $R=backtick($Q);
+if ($R=~/\berror: .*-fno-diagnostics-show-caret\b/) {
+  # gcc-4.6 and earlier don't have this flag, and they fail.
+  $Q=~s@ -fno-diagnostics-show-caret(?=\s)@@;
+  $DIAG="";
+  $R=backtick($Q);
+}
 
 if ($R!~/: warning: #warning\b/) {
   # config2.h:314:4: warning: #warning REQUIRES: c_lgcc3.o
   # Dat: g++-3.3 ignores #warning with -M -MG -E
-  $R.="\n".backtick("$GCCP -DOBJDEP -E 2>&1 >/dev/null @DSQ");
+  $R.="\n".backtick("$GCCP -DOBJDEP$DIAG -E 2>&1 >/dev/null @DSQ");
 }
 
 ## die $R;
--- rule.hpp	2013-04-18 12:14:20.385333527 +0200
+++ rule.hpp	2013-04-18 12:14:35.818870070 +0200
@@ -88,7 +88,7 @@
       PR_PNGAuto=15,
       PR_PNGAutoMaybe=25,
       PR_PNGAutoBadUnsigned=45,
-      PR_PNGAutoBadSigned=55,
+      PR_PNGAutoBadSigned=55
     END_STATIC_ENUM()
     pr_t Predictor;