Hi Guix,

I've noticed a strange error when attempting to build my software
against clang-toolchain.  I've attached a minimally breaking example,
but the gist of it is that RUNPATH validation fails as shown below.

  starting phase `validate-runpath'
  validating RUNPATH of 1 binaries in
  "/gnu/store/sd1zjjf13mi448qbqaphhcvf9ap5jxji-why-hello-0/bin"...
  /gnu/store/sd1zjjf13mi448qbqaphhcvf9ap5jxji-why-hello-0/bin/hello:
  error: depends on 'libfmt.so.9', which cannot be found in RUNPATH
  ("/gnu/store/gsjczqir1wbz8p770zndrpw4rnppmxi3-glibc-2.35/lib")

Is this expected?  I know that the -for-system have historically
disregarded the existence of clang-toolchain and hence led to issues,
but I think this is something else…

Cheers