Adam Majer pointed out in [1] the way were signing releases was
unusual. Neither Carl nor I could think of a good reason for
explicitely signing the checksum (internally of course that's what GPG
is going anyway).
[1] mid:b3fd556d-c346-7af9-a7a2-13b0f3235071@suse.de
Apparently some systems (MacOS?) have a system library called libutil
and the name conflict causes problems. Since this library is quite
notmuch specific, rename it to something less generic.
I noticed when trying to use VERSION (and derived variables) in a
subdirectory that the top level Makefile.local needed to be included
first. But according to c10085c77b it
actually needs to be last. To break this conflict, move the variables
definitions into a new Makefile.global.
