Name space pollution part 2

Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=651

Reported by David Hedbor, Idonex / Real Networks david@hedbor.org

This one causes numerous problems with embedded PHP. spider.c defines a non-static variable "empty_string". This is also used all over PHP4, where it's supposed to be a (char *)"". Naturally, this is BAD. Two patches will be attached. Please apply ASAP.