Add better support for armv7a cross compilation #2753

Job	Run time
unit-tests	4s
runghc	14s
tests-benchmarks	10s
cabal-doExactConfig	11s
cabal	10s
maintainer-scripts	7s
multi-target	30s
nix-build	35s
plan-extra-hackages	7s
shellFor-hoogle	8s
shellFor-multiple-package	10s
shellFor-not-depends	12s
shellFor-single-package	14s
build-extra-hackages	7s
check-materialization-concurrency	25s
check-path-support	4s
closure-size	3s
docs	20s
haskell-nix-roots-do-not-require-IFDs	9s
hix	25s
hix-cabal	7s
hydra-ifdLevel-0-and-1	6m 17s
hydra-ifdLevel-2	3m 24s
hydra-ifdLevel-3	3m 29s
hydra-without-remote-builders-ghc8107	11s
hydra-without-remote-builders-ghc9101	7s
nix-tools	13s
update-docs	5s
	18m 18s

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