Add package id getter function

[jmark]

In some scenarios it is useful to have a dedicated query function for the package id registered by libsc. For example, not all wrapper
generators or FFIs (foreign function interfaces) support to read global external variables.

[cburstedde]

Thanks!

[cburstedde]

Do you think you may rebase the change to have non-related commits disappear?

[cburstedde]

Do you think you may rebase the change to have non-related commits disappear?

Thanks again! For me to merge could you please simplify the history to a minimum @jmark? BR Carsten

[cburstedde]

Thanks for this useful contribution @jmark. It may help us to close #204 together with previous updates.
Would you find it ok to simplify this PR to one commit without the merges in the history?

[jmark]

@cburstedde I cleaned up the git history. Let me know if there is anything else to do.

[cburstedde]

@cburstedde I cleaned up the git history. Let me know if there is anything else to do.

Hi @jmark, thanks again and sorry to hassle you for this useful contribution.

The history as I see it contains some really old merges, such as PR #1 and #27. I'd feel more comfortable if you were to cherry-pick just the one commit with the code changes on the current master and discard the rest of the history.

In addition, if you might add a doc/author_markert.txt file the same way you did it with libsc?

[jmark]

@cburstedde All good and many thanks for your advice!