Error or feature in g10.c?

[Martin Lesser]

After updating from 1.0.6 to 1.0.7 we ran into problems with an app
which uses --run-as-shm-coprocess (gabber, see also
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=146740 )

I know that use of shm-routines in gnupg is deprecated and should be
replaced with --command-fd.

Since rev. 1.129.2.82 of g10.c there's an
  #undef USE_SHM_COPROCESSING
which in the current version is additionally commented with "huh ?"

What's the reason for inserting this #undef (especially at this point)?
In the archives I could not find any hint.

Commenting out this line solved the problem with gabber but I'm not sure
wether this is correct. IMO it is possible that other apps also make use
of the shm-routines. If so they could run into problems too.

Martin