It is constant and can just be replaced by $(SRCDIR)/solenv.
Use BUILD_TYPE where it was used to check if config_*.mk is sourced.
Change-Id: Ib9d480c57194b6340093aa47776f8768df69b7d1
The plugin is intentionally built using a custom Makefile,
because it's used by gbuild, so I don't want to build the plugin
using gbuild too. It is also intentionally not placed under workdir/,
as that is cleaned by 'make clean', the plugin is cleaned only
by 'make distclean', so that cleaning it doesn't cause ccache misses.
No actual functionality in the plugin itself yet.
Change-Id: Ic05eba8d6260eec123c9e699eb5385abfe1b832f
