scons: Tone down a fast model error into a warning.

If a fast model static library can't be found, we should treat that as
a warning instead of an error, and pass back the original library name
so that it can at least be added and potentially come from somewhere
else.

In practice, this is important because gem5 will be configured by SCons
indirectly in the future, using kconfig based tools that SCons runs on
the user's behalf. If SCons is misconfigured or not configured, this
error can trip, preventing those tools from starting. That creates a
catch 22, since you'd need SCons to fix the config, and SCons can't
run because of the config.

We can avoid that problem by making SCons more lenient, so that it can
still run even if it doesn't find static libraries where it might have
expected to.

Change-Id: Iadfd823b61fe96b937c2650250487d290492f265
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/58352
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed