Log Message:
Update devel/cmph to version 2.0.

Prompted by beta.repology.org.

News for version 2.0

   Cleaned up most warnings for the c code.

   Experimental C++ interface (--enable-cxxmph) implementing the
   BDZ algorithm in a convenient interface, which serves as the
   basis for drop-in replacements for std::unordered_map,
   sparsehash::sparse_hash_map and sparsehash::dense_hash_map.
   Potentially faster lookup time at the expense of insertion time.
   See cxxmpph/mph_map.h and cxxmph/mph_index.h for details.