Patch for isdigit/isalpha/etc. macro arguments

[Steve Ellcey]

> Sorry, you obviously spent some serious amount of time fixing this,
> but I think this is just gross.  It also would just hide the bug
> mentioned above.  I guess we should use -liberty's "safe-ctype.h"
> instead.

Hm, this seems to lead to some new problems.  safe-ctype.h defines
ISALNUM, ISALPHA, ISDIGIT, etc.  (uppercase) and if I start including
"safe-ctype.h" instead of <ctype.h>, then I collide with
readline/chardefs.h in some files (like cli/cli-dump.c) because that
file includes readline/readline.h which includes readline/chardefs.h
which has its own definitions of ISALNUM, ISALPHA, ISDIGIT, etc.

What to do?  My best guess would be to have readline/chardefs.h not
define these macros if they are already defined.  But now we are
reaching outside the gdb subdir.

Steve Ellcey
sje@cup.hp.com