referencing T1406 here since I can't update it on this bug tracker
T1406
also related to this bug
http://lists.gnupg.org/pipermail/gcrypt-devel/2011-July/001832.html
The simple solution I've found appears to be using 'static' in front of mpihelp_add_1 and
mpihelp_sub_1 declarations in mpi-internal.h, this solves compilation of gnupg 1.4 and I suspect
also of the libgcrypt case since mpi is the same.
I can produce a patch on the git repo if needed.
ciao