diff --git a/build/zoneinfo2lua.pl b/build/zoneinfo2lua.pl
old mode 100644
new mode 100755
index 7e772c0aff..2e24c95416
--- a/build/zoneinfo2lua.pl
+++ b/build/zoneinfo2lua.pl
@@ -6,6 +6,9 @@
 use strict;
 
 my %TZ;
+my $tzdir = $ARGV[0] || "/usr/share/zoneinfo";
+
+chdir($tzdir) || die "chdir($tzdir): $!\n";
 
 local $/ = "\012";
 open( ZTAB, "< ./zone.tab" ) || die "Unable to open zone.tab: $!";