Fixed some typos in BUILDING document. (#947) #493

Job	Run time
ci (tarm64osx, macos-14)	12s
ci (a6osx, macos-13)	12s
ci (arm64osx, macos-14)	13s
ci (ti3le, ubuntu-22.04)	12s
ci (ta6osx, macos-13)	12s
ci (tpb, ubuntu-22.04, --pb --threads --enable-libffi, test-some-fast)	12s
ci (i3le, ubuntu-22.04)	12s
ci (ta6le, ubuntu-22.04, CFLAGS+=-std=gnu89)	12s
ci (a6le, ubuntu-22.04)	12s
ci (a6nt, windows-2022, vs)	12s
ci (ta6le, ubuntu-22.04, reboot, -m=ta6le --force, re.boot SCHEME="chezscheme", test-some-fast)	12s
ci (ti3nt, windows-2022, vs)	12s
ci (i3nt, windows-2022, vs)	12s
ci (ta6le, ubuntu-22.04, test-more, more)	12s
ci (ta6nt, windows-2022, gcc, CFLAGS+=-std=gnu89)	12s
ci (ta6nt, windows-2022, vs)	12s
ci (tpb, ubuntu-22.04, --pb --threads --enable-libffi, test-some-fast)	30m 7s
ci (ta6osx, macos-13)	20m 4s
ci (a6osx, macos-13)	16m 43s
ci (arm64osx, macos-14)	12m 32s
ci (a6le, ubuntu-22.04)	9m 5s
ci (tarm64osx, macos-14)	14m 56s
ci (i3le, ubuntu-22.04)	12m 53s
ci (ta6le, ubuntu-22.04, reboot, -m=ta6le --force, re.boot SCHEME="chezscheme", test-some-fast)	9m 7s
ci (ti3nt, windows-2022, vs)	14m 49s
ci (ta6le, ubuntu-22.04, CFLAGS+=-std=gnu89)	12m 9s
ci (ti3le, ubuntu-22.04)	16m 45s
ci (i3nt, windows-2022, vs)	11m 36s
ci (ta6le, ubuntu-22.04, test-more, more)	58m 24s
ci (ta6nt, windows-2022, gcc, CFLAGS+=-std=gnu89)	13m 7s
ci (a6nt, windows-2022, vs)	12m 16s
ci (ta6nt, windows-2022, vs)	15m 20s
	4h 43m 6s

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