shim 15.3 release candidate 4
Hopefully the last release candidate. Here's the shortlog since rc3:
Chris Coulson (1):
Fix boot failures due to variable size constraints
Peter Jones (4):
Make 'make test' work on gcc 4.8.5
Don't set LIBDIR in CI builds any more.
Fix cross-compilation from x86_64->i686
Try multi-arch CI building using cross compilation