Hardware breakpoints in DJGPP port of GDB

[DJ Delorie]

Applied, sorry for the delay.

> The following change resurrects hardware breakpoints in the DJGPP port of 
> GDB, and avoid referencing a char array beyond its end:
> 
> 1999-06-26  Eli Zaretskii  <eliz@is.elta.co.il>
> 
> 	* config/i386/xm-go32.h (ROOTED_P): Don't reference X[1] if X[0]
> 	is a null character.
> 
> 	* config/i386/nm-go32.h (DECR_PC_AFTER_HW_BREAK): Define to 1.