The usual preset buildbot_linux,no_test does not work for arm32 right now, near the end of the process SPM complains that it can't find libicu (correct, it's not being copied over) when building the bootstrap SPM.

The result of this is that Swift 5.x on armv6/armv7 still requires the clang and libicu dependencies, but depending on an old system version of clang or an obsolete release of libicu (e.g. on distributions derived from Stretch/Buster) leads to issues like #148.