Compile error with clang++ 5 in geometry_within.hpp code

[springmeyer]

/home/travis/build/mapbox/mason/mason_packages/linux-x86_64/clang++/5.0.0/bin/clang++  -DMBGL_RENDER_BACKEND_OPENGL=1 -DRAPIDJSON_HAS_STDSTRING=1 -I../src -I../include -isystem ../vendor/mapbox-base/extras/kdbush.hpp/include -isystem ../vendor/mapbox-base/deps/supercluster.hpp/include -isystem ../vendor/mapbox-base/deps/shelf-pack-cpp/include -isystem ../vendor/mapbox-base/deps/geojson-vt-cpp/include -isystem ../vendor/boost/include -isystem ../vendor/csscolorparser -isystem ../vendor/earcut.hpp/include -isystem ../vendor/eternal/include -isystem ../vendor/parsedate -isystem ../vendor/polylabel/include -isystem ../vendor/protozero/include -isystem ../vendor/unique_resource -isystem ../vendor/vector-tile/include -isystem ../vendor/wagyu/include -isystem ../vendor/mapbox-base/include -isystem ../vendor/mapbox-base/extras/expected-lite/include -isystem ../vendor/mapbox-base/deps/geojson.hpp/include -isystem ../vendor/mapbox-base/deps/geometry.hpp/include -isystem ../vendor/mapbox-base/deps/jni.hpp/include -isystem ../vendor/mapbox-base/deps/optional -isystem ../vendor/mapbox-base/deps/pixelmatch-cpp/include -isystem ../vendor/mapbox-base/deps/variant/include -isystem ../vendor/mapbox-base/deps/cheap-ruler-cpp/include -isystem ../vendor/mapbox-base/extras/rapidjson/include -fPIC -std=c++11 -O3 -DNDEBUG -fPIC -fvisibility=hidden -fvisibility-inlines-hidden   -fno-rtti -Wall -Wshadow -Wextra -Werror -std=c++14 -MD -MT CMakeFiles/mbgl-core.dir/src/mbgl/style/expression/parsing_context.cpp.o -MF CMakeFiles/mbgl-core.dir/src/mbgl/style/expression/parsing_context.cpp.o.d -o CMakeFiles/mbgl-core.dir/src/mbgl/style/expression/parsing_context.cpp.o -c ../src/mbgl/style/expression/parsing_context.cpp
In file included from ../src/mbgl/style/expression/parsing_context.cpp:26:
In file included from ../include/mbgl/style/expression/within.hpp:5:
../src/mbgl/util/geometry_within.hpp:11:43: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
const WithinBBox DefaultBBox = WithinBBox{std::numeric_limits<int64_t>::max(),
                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[alexshalamov]

/cc @zmiao