Improve the description of USE=test to clearly indicate what the flag
does instead of claiming it workaround for Portage.
tcl - Add support the Tcl language
tcmalloc - Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd - Add support for TCP wrappers
-test - Workaround to pull in packages needed to run with FEATURES=test. Portage-2.1.2 handles this internally, so don't set it in make.conf/package.use anymore
+test - Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
theora - Add support for the Theora Video Compression Codec
threads - Add threads support for various packages. Usually pthreads
tidy - Add support for HTML Tidy