MFH: r481437 math/py-graphillion: Update to 1.2
This version fixes build failures on FreeBSD versions that use Clang 6:
src/graphillion/zdd.cc:461:31: error: invalid operands to binary expression ('std::1::ostream' (aka 'basic_ostream<char>') and 'std::1::ostream')
if (out == std::cout || out == std::cerr) ~~~ ^ ~~~~~~~~~
Reported by: pkg-fallout
Approved by: ports-secteam (miwi)