gas: rx: constify string to rx_error

[Alan Modra]

On Wed, Oct 19, 2011 at 12:01:57PM -0400, Mike Frysinger wrote:
> building rx's gas code atm fails:
> 
> rx-parse.c: In function ‘rx_parse’:
> rx-parse.c:3774:9: error: passing argument 1 of ‘rx_error’ discards ‘const’ 

I'm curious because I don't see this error.  What's the code here look
like?  What version of bison are you using?

> 2011-10-19  Mike Frysinger  <vapier@gentoo.org>
> 
> 	* config/rx-defs.h (rx_error): Add const to first arg.
> 	* config/rx-parse.y (rx_error): Likewise.

OK.

-- 
Alan Modra
Australia Development Lab, IBM