pokerfast bundles no third-party source.

The optional exact-equity helper (`pokerfast.equity`, `native/`) builds against
OMPEval, which is fetched as a git submodule into vendor/OMPEval and is NOT
redistributed here.

    OMPEval -- https://github.com/vkresch/OMPEval
               (a fork of https://github.com/zekyll/OMPEval)
    pinned at commit 725a819
    ISC License, Copyright (c) 2016, Timo A.

    OMPEval vendors libdivide, which carries its own licence; see
    vendor/OMPEval/LICENSE-libdivide.txt after initialising the submodule.

If you distribute a BINARY built by native/build.sh, it links OMPEval and you
must carry OMPEval's copyright and permission notice with it. The ISC licence
text travels with the submodule at vendor/OMPEval/LICENSE.txt.

`native/patches/0001-constexpr-urbg.patch` is a two-line change to OMPEval's
omp/Random.h making min()/max() constexpr, which newer C++ standard libraries
require of a UniformRandomBitGenerator. It is applied to the submodule working
tree at build time and is not committed upstream here.
