[build] write targets like "all:" that delegate to p-all, j-all etc. (whatever is available)

Author: moritz

Configure.pl

@@ -252,6 +252,15 @@
         );
     }
 
+    # write post-amble
+
+    my @prefixes = sort map substr($_, 0, 1), keys %backends;
+    print $MAKEFILE "\n# Makefile code generated by Configure.pl:\n";
+
+    for my $t (qw/all clean test qregex-test/) {
+        print $MAKEFILE "$t: ", join(' ', map "$_-$t", @prefixes), "\n";
+    }
+
     close $MAKEFILE
         or die "Error while writing to 'Makefile': $!";