WIP: Fix for m68k #1481

Job	Run time
build (libgccjit.so, master, --mini-tests)	8m 41s
build (libgccjit.so, master, --std-tests)	9m 55s
build (libgccjit.so, master, --test-libcore)	9m 59s
duplicates	4s
build (libgccjit.so, master, --extended-rand-tests)	13m 54s
build (libgccjit.so, master, --extended-regex-example-tests)	11m 52s
build (libgccjit.so, master, --extended-regex-tests)	20m 44s
build (libgccjit.so, master, --test-successful-rustc --nb-parts 2 --current-part 0)	21m 49s
build (libgccjit.so, master, --test-successful-rustc --nb-parts 2 --current-part 1)	17m 54s
build (libgccjit_without_int128.so, master-without-128bit-integers, --mini-tests)	9m 37s
build (libgccjit_without_int128.so, master-without-128bit-integers, --std-tests)	11m 25s
build (libgccjit_without_int128.so, master-without-128bit-integers, --test-libcore)	11m 16s
build (libgccjit_without_int128.so, master-without-128bit-integers, --extended-rand-tests)	13m 23s
build (libgccjit_without_int128.so, master-without-128bit-integers, --extended-regex-example-tests)	13m 45s
build (libgccjit_without_int128.so, master-without-128bit-integers, --extended-regex-tests)	24m 46s
build (libgccjit_without_int128.so, master-without-128bit-integers, --test-successful-rustc --nb-...	20m 35s
build (libgccjit_without_int128.so, master-without-128bit-integers, --test-successful-rustc --nb-...	19m 59s
	3h 59m 38s

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