gitweb: Precompile CGI routines for mod_perl

Following advice from CGI(3pm) man page, precompile all CGI routines
for mod_perl, in the BEGIN block.

  If you want to compile without importing use the compile() method
  instead:

    use CGI();
    CGI->compile();

  This is particularly useful in a mod_perl environment, in which you
  might want to precompile all CGI routines in a startup script, and then
  import the functions individually in each mod_perl script.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

gitweb/gitweb.perl

@@ -18,6 +18,10 @@
 use File::Basename qw(basename);
 binmode STDOUT, ':utf8';
 
+BEGIN {
+	CGI->compile() if $ENV{MOD_PERL};
+}
+
 our $cgi = new CGI;
 our $version = "++GIT_VERSION++";
 our $my_url = $cgi->url();