Meson

nixd/lib/Controller: use `CheckReturn` to simplify early-returns (NFC) #3257

Job	Run time
nix-build-develop-gcc (none, release, true)	3m 4s
nix-build-develop-gcc (none, release, false)	2m 59s
nix-build-develop-gcc (none, debug, true)	2m 44s
nix-build-develop-gcc (none, debug, false)	2m 52s
nix-build-develop-gcc (address, release, true)	4m 48s
nix-build-develop-gcc (address, release, false)	4m 50s
nix-build-develop-gcc (address, debug, true)	3m 57s
nix-build-develop-gcc (address, debug, false)	4m 12s
nix-build-develop-gcc (undefined, release, true)	4m 8s
nix-build-develop-gcc (undefined, release, false)	4m 4s
nix-build-develop-gcc (undefined, debug, true)	3m 17s
nix-build-develop-gcc (undefined, debug, false)	3m 18s
nix-build-develop-clang (none, release, true)	2m 51s
nix-build-develop-clang (none, release, false)	2m 54s
nix-build-develop-clang (none, debug, true)	2m 46s
nix-build-develop-clang (none, debug, false)	2m 37s
	55m 21s

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