error C2976: 'boost::intrusive::bucket_hash_equal_t',error C3203: 'bucket_hash_equal_t': unspecialized class template can't be used as a template argument for template parameter 'DeriveFrom', expected a real type on MSVC

[nnfdnkns]

Issue description: Found Boost\libs\interprocess build error C2976 ,error C3203 in MSVC, this issue can be reproduced on boostorg/boost@b5639bd. Could you please take a look?

Reproduce steps: 1.git clone -c core.autocrlf=true --recursive ​https://github.com/boostorg/boost.git F:\gitP\boostorg\boost 2.open a VS 2019 x64 command prompt and browse to F:\gitP\boostorg\boost 3..\bootstrap 4..\b2 headers variant=release --build-dir=..\out\amd64rel address-model=64 5..\b2 variant=release --build-dir=..\out\amd64rel address-model=64 6..\b2 -j16 variant=release --build-dir=..\out\amd64rel libs\interprocess\test address-model=64

ErrorMessage: error C2976: 'boost::intrusive::bucket_hash_equal_t': too few template arguments error C3203: 'bucket_hash_equal_t': unspecialized class template can't be used as a template argument for template parameter 'DeriveFrom', expected a real type ...failed compile-c-c++ F:\gitP\boostorg\boost\out\amd64rel\boost\bin.v2\libs\interprocess\test\iunordered_set_index_allocation_test.test\msvc-14.2\release\threading-multi\iunordered_set_index_allocation_test.obj...

log test.log.58.txt

[nnfdnkns]

Could you please take a look?Thank you!

[igaztanaga]

I can't reproduce this problem with current develop code, the iunordered_set_index_allocation_test tests looks ok.