As of bug 937901, we support building ICU when cross compiling from Linux->OSX. However, the '-g' flags are explicitly removed with --enable-debug, since ICU's configure tries to run dsymutil (as shown in obj/js/src/intl/icu/target/config.log) If we get a suitable dsymutil working in Linux for crashreporter, we should re-enable -g for ICU cross compiles.

What's it doing with dsymutil, any idea?

I'm not really sure - it looks like clang is trying to execute it, but can't find it since it doesn't exist on the host. Just grepping through ICU itself I don't see any mention of dsymutil, so I don't know why adding --enable-debug would only cause the ICU configure to fail. I've attached ICU target config.log in case you are curious.

Comments in the clang source indicate that it runs dsymutil when you compile and link in one command line (like `clang -o foo foo.cpp`) because otherwise the debug info would be lost in the temp object file: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Driver.cpp?annotate=130981&pathrev=131084#l662

I've got a working dsymutil as of bug 1205242, but it's named `llvm-dsymutil`, so I'm not sure this will fix the problem immediately. It should be possible to make it work, though.