gc fatal error: GC stage 500

Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=90

Reported by Honza Petrous hop@unibase.cz

Time to time Pike (7.1.5) is crashing Roxen (2.1.44) In debug log is:

gc.c:2144: Fatal error:
Pike was in GC stage 500 when this fatal occured:
Still got 3 external weak references to internal things in gc.
Attempting to dump backlog (may fail)...
Backtrace at time of fatal:
etc/modules/RXML.pmod/PXml.pike: __INIT()
etc/modules/RXML.pmod/PXml.pike:
clone(RXML.Context,RXML.t_text,RXML.TagSet("use
r_tag_contents+rxml_tag_set,Administration Interface",35),mapping[16],0)
etc/modules/RXML.pmod/module.pmod:3123:
get_parser(RXML.Context,0,RXML.PXml(RXML
.Context,RXML.t_text,RXML.TagSet("user_tag_contents+rxml_tag_set,Administra
tion
Interface",35)))
etc/modules/RXML.pmod/module.pmod:1906:
_exec_array(RXML.PXml(RXML.Context,RXML.
t_text,RXML.TagSet("user_tag_contents+rxml_tag_set,Administration
Interface",35)
),({" <translate id=\"bA\">Save</translate> "}),0)
etc/modules/RXML.pmod/module.pmod:2380:
_eval(RXML.PXml(RXML.Context,RXML.t_text
,RXML.TagSet("user_tag_contents+rxml_tag_set,Administration
Interface",35)),([]),"")
[ ... ]