#472 Reproducible build of pic libraries

[Philipp Klaus Krause]

Reproducible builds are a good thing.
However, there are some remaining reproducibility issues with SDCC. One is that builds of pic libraries are not reproducible, i.e. building the pic libraries twice from the same source using the same SDCC will result in different binaries.
I guess, something similar to what I did in rev #9407 for the non-pic libraries needs to be done for pic to fix this.

Philipp