Extract cross-compiling vars #2511

Job	Run time
clang-sanitizers (,thread)	2m 30s
Cross Compile linux-armv6	2m 1s
Cross Compile linux-armv7	1m 59s
Cross Compile linux-arm64	1m 49s
Cross Compile android-armv7	2m 13s
clang-sanitizers (,address,undefined)	2m 2s
downstream	43m 27s
freebsd	9m 34s
linux-compat (manylinux1-x64)	1m 5s
linux-compat (manylinux1-x86)	1m 14s
linux-compiler-compat (clang-3)	1m 54s
linux-compat (manylinux2014-x64)	1m 26s
linux-compiler-compat (clang-6)	6m 7s
linux-compat (manylinux2014-x86)	1m 31s
linux-compiler-compat (clang-8)	6m 27s
linux-compat (raspbian-bullseye)	6m 48s
linux-compiler-compat (clang-9)	6m 14s
linux-compat (fedora-34-x64)	1m 22s
linux-compiler-compat (clang-10)	1m 52s
linux-compat (opensuse-leap)	1m 40s
linux-compiler-compat (clang-11)	1m 56s
linux-compat (rhel8-x64)	1m 5s
linux-compiler-compat (gcc-4.8)	1m 28s
linux-compat (al2-x64)	1m 17s
linux-compiler-compat (gcc-5)	1m 50s
linux-compiler-compat (gcc-6)	1m 47s
linux-compiler-compat (gcc-7)	1m 50s
linux-debug	1m 51s
linux-compiler-compat (gcc-8)	1m 54s
linux-compiler-compat (gcc-11)	3m 8s
linux-no-cpu-extensions	1m 40s
linux-shared-libs	1m 34s
macos	1m 31s
macos-debug	1m 27s
macos-no-cpu-extensions	1m 38s
macos-x64	2m 42s
windows	2m 24s
openbsd	12m 11s
windows-app-verifier	23m 28s
windows-debug	2m 30s
windows-no-cpu-extensions	1m 45s
windows-shared-libs	3m 47s
windows-vc14 (x86)	1m 43s
windows-vc15 (x86)	3m 9s
windows-vc14 (x64)	2m 1s
windows-vc15 (x64)	2m 46s
windows-vc16 (x86)	1m 47s
windows-vc16 (x64)	1m 47s
	3h 11m 11s

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