There is leftover markup from the texinfo source in the manual page for gcc(1). Specifically, search for @pxref and @anchor, which shouldn't be showing up in the output.

Also, the documentation for -print-multi-lib seems to be mangled:

-print-multi-lib
    Print the mapping from multilib directory names to compiler
    switches that enable them.  The directory name is separated from
    the switches by ;, and each switch starts with an @} instead of the
    @samp{-, without spaces between multiple switches.  This is sup-
    posed to ease shell-processing.

(You can't see it here, but "instead of the" is bold as well; it should not be.) This should likely read:

-print-multi-lib
    Print the mapping from multilib directory names to compiler
    switches that enable them.  The directory name is separated from
    the switches by ;, and each switch starts with an @ instead of the
    -, without spaces between multiple switches.  This is supposed
    to ease shell-processing.

The source which generates this manpage is in gcc/doc/invoke.texi.