Make llvm version configurable #369

Job	Run time
windows (windows, Release, amd64)	13m 11s
Linux (bun-webkit-linux-amd64-debug, big-ubuntu, x64, Debug)	16m 31s
windows (windows, Debug, amd64, -debug)	13m 21s
macOS (macos-13-large, haswell, bun-webkit-macos-amd64-debug, /usr/local/opt, x64, Debug)	3m 4s
Linux (bun-webkit-linux-arm64-debug, linux-arm64-gh, arm64, Debug)	21m 26s
macOS (macos-13-xlarge, native, bun-webkit-macos-arm64-debug, /opt/homebrew/opt, arm64, Debug)	3m 5s
Linux (-flto=full -fwhole-program-vtables -fforce-emit-vtables, bun-webkit-linux-arm64-lto, linux...	32m 24s
macOS (macos-13-large, -flto=full -fwhole-program-vtables -fforce-emit-vtables, haswell, bun-webk...	3m 4s
Linux (bun-webkit-linux-arm64, linux-arm64-gh, arm64, Release)	20m 8s
macOS (macos-13-large, haswell, bun-webkit-macos-amd64, /usr/local/opt, x64, Release)	3m 1s
Linux (-flto=full -fwhole-program-vtables -fforce-emit-vtables, bun-webkit-linux-amd64-lto, big-...	23m 48s
macOS (macos-13-xlarge, -flto=full -fwhole-program-vtables -fforce-emit-vtables, native, bun-webk...	2m 47s
Linux (bun-webkit-linux-amd64, big-ubuntu, x64, Release)	15m 0s
macOS (macos-13-xlarge, native, bun-webkit-macos-arm64, /opt/homebrew/opt, arm64, Release)	2m 57s
release	0s
	2h 53m 47s

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