fix(DAlphaBall make): Avoid duplicate symbols linker error

[rebelot]

trafficstars

Declare-only gmp globals in header file and define them in only one source file

[rebelot]

@rebelot Could you please sign the Rosetta Contributor Licensing Agreement at https://www.rosettacommons.org/forms/cla ? (See https://github.com/RosettaCommons/rosetta/blob/main/CONTRIBUTING.md for more info.)

signed 👌

[ajasja]

@roccomoretti Who are the people with the magic merge powers? I think we should aim to have as little open PRs as possible...

[roccomoretti]

They're the @can_merge_to_main team. (And should be able to be pinged as such.)

Agreed that we want to minimize the number of open PRs. This one unfortunately slipped through the cracks. (Sorry @rebelot.)