Portage overlay aimed to fix some ebuilds from `sci-electronics` and `sci-mathematics` and eventually make an OpenROAD ebuild.

Ebuild files taken from the official Gentoo repository.

## Currently available:
* `dev-libs/boost` & `dev-libs/boost-static` - a hacky way to get static Boost libraries using a second ebuild, not all USE flags are tested!
* `sci-electronics/graywolf` - new ebuild, the stable version fails to link.
* `sci-electronics/magic` - updated to a newer version and set `-std=gnu89` permanently, used to fail to compile because of `termio.h` and old-style function declarations mixed with C99-style comments.
* `sci-electronics/opensta` - new ebuild, the stable version needs SWIG 3.0, which is no longer available in the Gentoo repo, the live ebuild merges fine.
* `sci-electronics/opentimer` - new ebuild.
* `sci-electronics/qflow` - new ebuild.
* `sci-electronics/qrouter` - new ebuild, patched to fix "undefined symbol" errors.
* `sci-libs/lemon` - updated for C++20 compatibility.
* `sci-mathematics/cudd` - building documentation fails with a modern C++ compiler, this ebuild just skips the docs.
* `sci-mathematics/papilo` - new ebuild, may fail because of Boost program\_options.
* `sci-mathematics/scip` - new ebuild, has a lot of options, not all are enabled - will probably be with the arrival of more ebuilds in this repo
* `sci-mathematics/soplex` - new ebuild.