Fix PR diagnostic/17594

[Neil Booth]

Matt Kraai wrote:-

> Howdy,
> 
> GCC does not error about unknown options that start with a valid
> option because it accepts matches against options that are a prefix of
> the input, even if they do not allow joined arguments, as a switch
> meant for another language.
> 
> The attached patch makes it require that the switch match exactly or
> accept a joined argument in order to accept it as meant for another
> language.  Tested on powerpc-unknown-linux-gnu.  OK to commit?
> 
> -- 
> Matt
> 
> (For gcc)
> 	* opts.c (find_opt): Require that the input match a switch
> 	exactly or that the switch take a joined option to be
> 	interpreted as a match for another language.
> 
> (For gcc/testsuite)
> 	* gcc.dg/funroll-loops-all.c: New.

This is fine, thanks.

Neil.