The built-in operator takes signed int. So, match it, such that
the built-in is never a better or equally-good match to our operator.
Fixes "ambiguous overload" errors from gcc 4.2 and VS 2008.
See https://github.com/harfbuzz/harfbuzz/issues/1374
I wonder if there's something better to do about these :(.
In file included from hb-ot-color.cc:31:
hb-ot-color-cpal-table.hh: In member function 'unsigned int OT::CPAL::get_size() const':
hb-ot-color-cpal-table.hh:118: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-ot-vorg-table.hh:96: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-vector.hh:87: note: candidate 1: const Type& hb_vector_t<Type, PreallocedCount>::operator[](unsigned int) const [with Type = OT::VertOriginMetric, unsigned int PreallocedCount = 8u]
hb-ot-vorg-table.hh:96: note: candidate 2: operator[](const T*, int) <built-in>
hb-ot-layout-gsubgpos.hh:1707: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
...
In file included from hb-ot-name.cc:29:
hb-ot-name-table.hh: In member function 'unsigned int OT::name::get_size() const':
hb-ot-name-table.hh:157: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-open-type.hh:354: note: candidate 1: const Type& OT::UnsizedArrayOf<Type>::operator[](unsigned int) const [with Type = OT::NameRecord]
hb-ot-name-table.hh:157: note: candidate 2: operator[](const T*, int) <built-in>
hb-ot-name-table.hh: In member function 'void OT::name::accelerator_t::init(hb_face_t*)':
hb-ot-name-table.hh:196: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:196: note: candidate 2: operator[](T*, int) <built-in>
hb-ot-name-table.hh:197: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:197: note: candidate 2: operator[](T*, int) <built-in>
hb-ot-name-table.hh:198: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second:
hb-dsalgs.hh:574: note: candidate 1: Type& hb_array_t<Type>::operator[](unsigned int) const [with Type = const OT::NameRecord]
hb-ot-name-table.hh:198: note: candidate 2: operator[](T*, int) <built-in>
make[4]: *** [libharfbuzz_la-hb-ot-name.lo] Error 1
make[3]: *** [all-recursive] Error 1
