how do you get gcc (or llvm) to generate ARM code from the OSX command-line?

On OSX 10.6.4 with iPhone SDK and Xcode 3.2.1 installed:

$ gcc foo.c -arch arm

gcc-4.2: error trying to exec '/usr/bin/arm-apple-darwin10-gcc-4.2.1':execvp: No such f开发者_如何学运维ile or directory

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$ /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/clang -O3 -arch armv7 bar.c -c