This still inflates the docker image chain since it's done in
a separate RUN command though.
This tests that one still can (re)build
compiler-rt/libunwind/libcxxabi/libcxx after stripping down the llvm
installation.
For x86 architectures, binutils objcopy and strip can be used as
such.
For armv7 and aarch64, binutils doesn't recognize the architectures
and refuse to touch the files. For most/everything that objcopy/strip
do, the actual architecture doesn't really matter though. Therefore,
provide a wrapper script and a minimal tool for editing PE executables,
that change the architecture from armv7 and aarch64 to i686 and x86_64
respectively before invoking binutils, and change it back afterwards.
In case the binutils tools are missing, just return a successful result
without doing anything for stripping operations (previously, we had the
<triplet>-strip tool symlinked to /bin/true, so this isn't any worse than
before) and fail for other objcopy operations.
gcc/libssp's configure script runs checks for flags that clang doesn't
implement. We actually just need to set a few HAVE defines and compile
the .c sources, so just check out this subdirectory using svn and build
it using a custom makefile.