|| !strcmp (STR, "Tbss") || !strcmp (STR, "include") \
|| !strcmp (STR, "imacros") || !strcmp (STR, "aux-info") \
|| !strcmp (STR, "idirafter") || !strcmp (STR, "iprefix") \
- || !strcmp (STR, "iwithprefix") || !strcmp (STR, "iwithprefixbefore"))
+ || !strcmp (STR, "iwithprefix") || !strcmp (STR, "iwithprefixbefore") \
+ || !strcmp (STR, "isystem"))
#ifndef WORD_SWITCH_TAKES_ARG
#define WORD_SWITCH_TAKES_ARG(STR) DEFAULT_WORD_SWITCH_TAKES_ARG (STR)