Revert "vanir_config v1.0.1: introduce a centralized location for custom build flags"

you have failed to grasp the intentions of vanir_config.

This reverts commit e0e0adae8d565df6ae4f4aea67c52187d24079a4.

Change-Id: Ib0081c2870e561eff3d5ab04c424b8387f73c63d