-my $builddir = "builds/$build_number";
-mkdir "builds" or die "builds: mkdir: $!\n" if ! -d "builds";
-mkdir $builddir or die "$builddir: mkdir: $!\n";
+if (!defined ($builddir)) {
+ $builddir = "builds/$build_number";
+ mkdir "builds" or die "builds: mkdir: $!\n" if ! -d "builds";
+}
+-d $builddir or mkdir $builddir or die "$builddir: mkdir: $!\n";
+my $abs_builddir = File::Spec->rel2abs ($builddir);