PERLVAR(Isortstash, HV *) /* which is in some package or other */
PERLVAR(Ifirstgv, GV *) /* $a */
PERLVAR(Isecondgv, GV *) /* $b */
-PERLVAR(Isortstack, AV *) /* temp stack during pp_sort() */
-PERLVAR(Isignalstack, AV *) /* temp stack during sighandler() */
PERLVAR(Imystrk, SV *) /* temp key string for do_each() */
PERLVAR(Idumplvl, I32) /* indentation level on syntax tree dump */
PERLVAR(Ioldlastpm, PMOP *) /* for saving regexp context during debugger */