Correctly handle "master" feature #323

Job	Run time
build_system	21s
build (gcc-13.deb, --mini-tests)	5m 24s
build (gcc-13.deb, --std-tests)	5m 45s
duplicates	2s
build (gcc-13.deb, --test-libcore)	13m 18s
build (gcc-13.deb, --extended-rand-tests)	8m 5s
build (gcc-13.deb, --extended-regex-example-tests)	5m 54s
build (gcc-13.deb, --extended-regex-tests)	12m 8s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 47s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 22s
build (gcc-13.deb, --projects)	17m 49s
build (gcc-13-without-int128.deb, --mini-tests)	5m 38s
build (gcc-13-without-int128.deb, --std-tests)	5m 48s
build (gcc-13-without-int128.deb, --test-libcore)	13m 18s
build (gcc-13-without-int128.deb, --extended-rand-tests)	7m 50s
build (gcc-13-without-int128.deb, --extended-regex-example-tests)	6m 10s
build (gcc-13-without-int128.deb, --extended-regex-tests)	11m 20s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 13s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 46s
build (gcc-13-without-int128.deb, --projects)	17m 52s
	3h 2m 50s

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