GHA: install gpatch on macOS #235

Job	Run time
archives-cache	3s
build (ubuntu-latest, 4.02.3)	9m 0s
build (ubuntu-latest, 4.03.0)	9m 17s
build (ubuntu-latest, 4.04.2)	9m 25s
build (ubuntu-latest, 4.05.0)	9m 20s
build (ubuntu-latest, 4.06.1)	9m 17s
build (ubuntu-latest, 4.07.1)	9m 10s
build (ubuntu-latest, 4.08.1)	3m 18s
build (ubuntu-latest, 4.09.1)	3m 35s
build (ubuntu-latest, 4.10.2)	3m 22s
build (ubuntu-latest, 4.11.2)	3m 21s
build (ubuntu-latest, 4.12.1)	3m 23s
build (ubuntu-latest, 4.13.1)	3m 13s
build (ubuntu-latest, 4.14.0)	3m 8s
build (ubuntu-latest, 5.0.0~beta2)	1m 32s
build (macos-latest, 4.12.0)	4m 18s
hygiene	14s
solvers (ubuntu-latest, 4.12.0, z3)	8m 48s
solvers (ubuntu-latest, 4.12.0, 0install)	8m 53s
cold (ubuntu-latest, 4.12.0)	3m 7s
test (ubuntu-latest, 4.12.0)	12m 27s
solvers (macos-latest, 4.12.0, z3)	7m 21s
upgrade (ubuntu-latest, 4.12.0)	2m 0s
test (macos-latest, 4.12.0)	19m 36s
solvers (macos-latest, 4.12.0, 0install)	7m 9s
upgrade (macos-latest, 4.12.0)	2m 57s
	2h 37m 14s

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