Comment 12 for bug 528377

It's not acceptable to default to the cpu on the build host.
Mono is going to need /proc also for other things on Linux, so it's a bit futile to break mono on other setups to try and avoid it.
As I said, you could check that cpuinfo is for arm and if it isn't, assume it's the broken qemu and that armv5+ is available.
In addition or as an alternative you could allow the flags to e set from an env var, so you can set that when running on a broken system.
Something like:
MONO_CPU_ARCH="armv5 thumb" mono ...