fix support for older C++11 compilers for python bindings
fix support for older C++11 compilers for python bindings

Summary:
The issue was reported here : https://github.com/facebookresearch/fastText/issues/678
gcc 4.8.5 seems to not support `auto` as lambda parameters.

Reviewed By: piotr-bojanowski

Differential Revision: D13136421

fbshipit-source-id: e1770c80f78f1b6578b8750059fe8c9220265f24

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