make: ccache leads to differing binaries

[kaspar030]

Description

Currently, modules are built by cd'ing into the module folder, then calling gcc with the absolute path of a source file. ccache strips absolute paths in order to cache properly.

This leads to different binaries depending on whether ccache has a cache hit or miss, or if it is used at all, if a source file uses e.g., __FILE__.

See #14262 for a possible fix.

Steps to reproduce the issue

Expected results

Actual results

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