gcc/ChangeLog:
* doc/extend.texi: Add missing @option.
an error. On some targets tail calls may never be supported.
Tail calls cannot reference locals in memory, which may affect
builds without optimization when passing small structures, or passing
-or returning large structures. Enabling -O1 or -O2 can improve
-the success of tail calls.
+or returning large structures. Enabling @option{-O1} or @option{-O2} can
+improve the success of tail calls.
@end table
@node Attribute Syntax