scons: Fix an error about an unrecognized compiler.

join was being passed a series of strings to join as separate
arguments like os.path.join, but it expects to get them as members of a
single sequence.

Change-Id: Id88ce4e9c5400f256a1af6351b4a964af0036b72
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25203
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed