[FS#837] PROVIDES handling for non-virtual packages

[LEDE Bugs]

The following task has a new comment added:

FS#837 - PROVIDES handling for non-virtual packages
User who did this - Jo-Philipp Wich (jow-)

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>  I expect this can be solved by separating the “vdepends” list from the package list, making each package provide itself, and always resolving DEPENDS through vdepends.

This is actually how opkg works internally as well so it might make sense to align behaviour here.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=837#comment2782