gh-117787: configure: fix bashisms/semantic breakage of iOS checks #1

Job	Run time
i686-pc-windows-msvc/msvc (Debug)	16m 39s
i686-pc-windows-msvc/msvc (Release)	22m 20s
x86_64-pc-windows-msvc/msvc (Debug)	17m 5s
x86_64-pc-windows-msvc/msvc (Release)	21m 48s
aarch64-pc-windows-msvc/msvc (Debug)	4m 55s
aarch64-pc-windows-msvc/msvc (Release)	5m 49s
x86_64-apple-darwin/clang (Debug)	15m 28s
x86_64-apple-darwin/clang (Release)	13m 9s
aarch64-apple-darwin/clang (Debug)	8m 25s
aarch64-apple-darwin/clang (Release)	13m 12s
x86_64-unknown-linux-gnu/gcc (Debug)	7m 35s
x86_64-unknown-linux-gnu/gcc (Release)	17m 36s
x86_64-unknown-linux-gnu/clang (Debug)	8m 4s
x86_64-unknown-linux-gnu/clang (Release)	13m 54s
aarch64-unknown-linux-gnu/gcc (Debug)	1h 3m 2s
aarch64-unknown-linux-gnu/gcc (Release)	47m 5s
aarch64-unknown-linux-gnu/clang (Debug)	54m 10s
aarch64-unknown-linux-gnu/clang (Release)	31m 14s
	6h 21m 30s

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