This fixes these nightly failing tests: https://jenkins.gem5.org/job/nightly/609/ Due to this commit: https://gem5-review.googlesource.com/c/public/gem5/+/68758 The source files are not copied to the "build" directory by default. This caused the systemc tests to fail as the "util/systemc/gem5_within_systemc/Makefile" depends on generated source files in the "build" directory. This patch adds the "--duplicate-sources" flag to the building of the ARM binaries necessisary for running systemc. The README has been updated to reflect this. Change-Id: I3006005e43276097be98f7d4685f3d98c180d3f9 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70860 Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Bobby Bruce <bbruce@ucdavis.edu> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com>