Can we use safe-ctype.h in a library?

[Thomas Koenig via Gcc-patches]

Hi,

I am currently looking at making libgfortran use the
TOUPPER et al functions from ctype-safe.h.  Adding this
in a gfortran header results in lots of
Gcc/trunk-bin/x86_64-pc-linux-gnu/./libgfortran/.libs/libgfortran.so: 
undefined reference to `_sch_istable'

errors.

So, can we use this, or should we just define this ourselves with
something like

#define TOUPPER(a) toupper ((unsigned char) (a))

?

Regards

        Thomas