[commit] Constant propogate unpack_long(), arm-elf can be built with -Werror

[Andrew Cagney]

Hello,

This changes the function declaration:

   extern LONGEST unpack_long (struct type *type, char *valaddr);

to:

   extern LONGEST unpack_long (struct type *type, const char *valaddr);

and then fixes the fallout (modify callees so that they, too, take a 
`const char *'; repeat).

This in turn makes it possible for arm-elf to compile with -Werror 
(Ya!).  The MAINTAINERS file is updated accordingly.

committed,
Andrew