fix error use 'template' keyword to treat 'item'

[0x0000dead]

Compile with CMAKE_CXX_STANDARD 17; Apple clang version 12.0.0 (clang-1200.0.32.29), getting an error:

../../Segmentor.h:187:21: error: use 'template' keyword to treat 'item' as a dependent template name loss_sum += loss.item<float>();

According to ISO C++03 14.2/4 fix it.

When the name of a member template specialization appears after . or -> in a postfix-expression, or after nested-name-specifier in a qualified-id, and the postfix-expression or qualified-id explicitly depends on a template-parameter (14.6.2), the member template name must be prefixed by the keyword template. Otherwise the name is assumed to name a non-template.

[AllentDan]

Hi, thanks for your PR. Is there anywhere else that should be fixed to compatipate with c++ 17? For instance, the training part or other model architectures.

[0x0000dead]

Hi, yes, training and different models, everything works fine.
This fix was not part of C++17 or C++14 Standard, but clang - compatibility. I expect that you compile the project with g++, I use clang and fix it up. Also, I use C++17 - there is no error at all, so you can also update CMakeLists.txt

[AllentDan]

Alright, we may leave the CMakeLists.txt configuration to customers' preference.

[AllentDan]

LGTM