Bug 621597: Make mod_perl.pl do the INC configuration itself, instead of

docs/en/xml/installation.xml

@@ -1132,7 +1132,7 @@ max_allowed_packet=4M
                 </warning> 
                 
                 <programlisting>
-    PerlSwitches -I/var/www/html/bugzilla -I/var/www/html/bugzilla/lib -w -T
+    PerlSwitches -w -T
     PerlConfigRequire /var/www/html/bugzilla/mod_perl.pl
                 </programlisting>
             </step>

mod_perl.pl

@@ -18,6 +18,13 @@
 package Bugzilla::ModPerl;
 use strict;
 
+# This sets up our libpath without having to specify it in the mod_perl
+# configuration.
+use File::Basename;
+use lib dirname(__FILE__);
+use Bugzilla::Constants ();
+use lib Bugzilla::Constants::bz_locations()->{'ext_libpath'};
+
 # If you have an Apache2::Status handler in your Apache configuration,
 # you need to load Apache2::Status *here*, so that any later-loaded modules
 # can report information to Apache2::Status.
@@ -36,7 +43,6 @@ use Bugzilla ();
 # Loading Bugzilla.pm doesn't load this, though, and we want it preloaded.
 use Bugzilla::BugMail ();
 use Bugzilla::CGI ();
-use Bugzilla::Constants ();
 use Bugzilla::Extension ();
 use Bugzilla::Install::Requirements ();
 use Bugzilla::Util ();