Workaround for GNUC 5.2.0 failing two tests
Workaround for GNUC 5.2.0 failing two tests

- string_span.t.cpp:278: failed: string_span: Allows to construct a cstring_span from a const C-array: sv.length() == size_type( 5 ) for 0 == 5
- string_span.t.cpp:539: failed: string_span: Allows to construct a cwstring_span from a const C-array: sv.length() == size_type( 5 ) for 0 == 5

martinmoene/gsl-lite,decaf-emu/gsl-lite,martinmoene/gsl-lite,martinmoene/gsl-lite,decaf-emu/gsl-lite