...on macOS with case-insensitive file systems.  When compiling e.g.
workdir/UnpackedTarball/gpgmepp/lang/cpp/src/parser/exception.cpp, libtool adds
-I../../.. (presumably to find files like
workdir/UnpackedTarball/gpgmepp/config.h), and including e.g. <string>
internally includes <version> now, and workdir/UnpackedTarball/gpgmepp/VERSION
happens to win.  So just remove VERSION from the sources, which appears to not
be needed at least in our build of gpgmepp.  (An alternative approach might have
been to use -iquote../../.. instead of -I../../.., but that's probably hard to
shoehorn into the libtool-generated compiler invocation.)

Change-Id: Ib1a30a6b825cab208238d17ff384e7900a27047d
Reviewed-on: https://gerrit.libreoffice.org/61359
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>