GNUPMDRV ever used?

[sfeam (E. Merritt) <eam...@gm...>]

I'm trying to clean out dead code, and came across several
places that refer to a symbol GNUPMDRV
For example:

# ifdef GNUPMDRV
    DosBeep(444, 111);
# endif

But so far as I can see, this symbol will never be defined
and therefore this is dead code.  

Am I missing something?
In particular, is there some undocumented build procedure
for OS2/PM that defines this symbol directly via a compiler
command rather than in a source file?

If not, then it can be removed from
src/mouse.c		- tested but never defined
src/gpexecute.c	- tested but never defined
src/os2/gclient.c - defined but never used