Add Debian paths to defaults

This change adds a number of default paths that Debian uses to hipcc so that clang can find the Debian packages without the user needing to set a bunch of environment variables (as is currently the case in rocrand).

It should, however, still be possible to set the environment variables to change from the defaults that are being set by these patches.

mentioned in merge request rocrand!2 (merged)

mentioned in commit cgmb/rocrand@d0413c4f

mentioned in merge request rocrand!3 (merged)

mentioned in commit cgmb/rocrand@ed2cee9c

mentioned in commit db44b3d4

merged