installer: make rewrite-config.PL change only defined parameters

Previously, it tried to slurp up all text between two
occurences of '__'

diff --git a/rewrite-config.PL b/rewrite-config.PL
index 5a372a0..9f4297a 100644 (file)
--- a/rewrite-config.PL
+++ b/rewrite-config.PL
@@ -115,7 +115,7 @@ foreach $key (keys %configuration) {
 
 $fname = $ARGV[0];
 $file = read_file($fname);
-$file =~ s/__.*?__/$configuration{$&}/seg;
+$file =~ s/__.*?__/exists $configuration{$&} ? $configuration{$&} : $&/seg;
 chmod 0644, $fname;
 open(OUTPUT,">$fname") || die "Can't open $fname for write: $!";
 print OUTPUT $file;