try to fix missing constant symbols

[h-vetinari]

Driven by errors with sentencepiece

word_model.obj : error LNK2001: unresolved external symbol "enum absl::lts_20211102::container_internal::ctrl_t const * const absl::lts_20211102::container_internal::kEmptyGroup" (?kEmptyGroup@container_internal@lts_20211102@absl@@3QBW4ctrl_t@123@B) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]
bpe_model.obj : error LNK2001: unresolved external symbol "enum absl::lts_20211102::container_internal::ctrl_t const * const absl::lts_20211102::container_internal::kEmptyGroup" (?kEmptyGroup@container_internal@lts_20211102@absl@@3QBW4ctrl_t@123@B) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]
char_model.obj : error LNK2001: unresolved external symbol "enum absl::lts_20211102::container_internal::ctrl_t const * const absl::lts_20211102::container_internal::kEmptyGroup" (?kEmptyGroup@container_internal@lts_20211102@absl@@3QBW4ctrl_t@123@B) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]
model_interface.obj : error LNK2001: unresolved external symbol "enum absl::lts_20211102::container_internal::ctrl_t const * const absl::lts_20211102::container_internal::kEmptyGroup" (?kEmptyGroup@container_internal@lts_20211102@absl@@3QBW4ctrl_t@123@B) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]
unigram_model.obj : error LNK2001: unresolved external symbol "enum absl::lts_20211102::container_internal::ctrl_t const * const absl::lts_20211102::container_internal::kEmptyGroup" (?kEmptyGroup@container_internal@lts_20211102@absl@@3QBW4ctrl_t@123@B) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]
model_interface.obj : error LNK2019: unresolved external symbol "private: static void const * const absl::lts_20211102::hash_internal::MixingHashState::kSeed" (?kSeed@MixingHashState@hash_internal@lts_20211102@absl@@0QEBXEB) referenced in function "unsigned __int64 __cdecl absl::lts_20211102::container_internal::DecomposePair<struct absl::lts_20211102::container_internal::raw_hash_set<struct absl::lts_20211102::container_internal::FlatHashMapPolicy<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,unsigned char>,struct absl::lts_20211102::container_internal::StringHash,struct absl::lts_20211102::container_internal::StringEq,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,unsigned char> > >::HashElement,struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,unsigned char> &>(struct absl::lts_20211102::container_internal::raw_hash_set<struct absl::lts_20211102::container_internal::FlatHashMapPolicy<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,unsigned char>,struct absl::lts_20211102::container_internal::StringHash,struct absl::lts_20211102::container_internal::StringEq,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,unsigned char> > >::HashElement &&,struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,unsigned char> &)" (??$DecomposePair@UHashElement@?$raw_hash_set@U?$FlatHashMapPolicy@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@container_internal@lts_20211102@absl@@UStringHash@234@UStringEq@234@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@std@@@std@@@container_internal@lts_20211102@absl@@AEAU?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@std@@@container_internal@lts_20211102@absl@@YA_K$$QEAUHashElement@?$raw_hash_set@U?$FlatHashMapPolicy@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@container_internal@lts_20211102@absl@@UStringHash@234@UStringEq@234@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@std@@@std@@@012@AEAU?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@E@std@@@Z) [D:\bld\sentencepiece-split_1646223867511\work\build\src\sentencepiece.vcxproj]

And some musings here:

A lot of the symbols on the sentencepiece side resolved themselves once I enforced the C++ standard, but some missing symbols remain - I'm still struggling to understand where these symbols go missing in the upstream CMake infra, though the patterns seems to be that they are all constants; in the case I'm hitting for sentencepiece, e.g. container_internal::kEmptyGroup, and same for hash_internal::MixingHashState::kSeed.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.