Add better support for armv7a cross compilation #2945

Job	Run time
build-extra-hackages	25s
cabal	21s
cabal-doExactConfig	53s
check-materialization-concurrency	19s
check-path-support	52s
closure-size	3s
docs	18m 3s
haskell-nix-roots-do-not-require-IFDs	8s
hix	43s
hix-cabal	14s
hydra-ifdLevel-0-and-1	1m 38s
hydra-ifdLevel-2	13m 7s
hydra-ifdLevel-3	30m 17s
hydra-without-remote-builders-ghc9101	12s
hydra-without-remote-builders-ghc966	11s
maintainer-scripts	11s
multi-target	11s
nix-build	10s
nix-tools	11s
runghc	7s
plan-extra-hackages	9s
shellFor-hoogle	15s
shellFor-multiple-package	11s
shellFor-not-depends	11s
shellFor-single-package	25s
tests-benchmarks	9s
unit-tests	5s
update-docs	8s
	1h 9m 49s

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