port https://github.com/mapbox/mapbox-gl-js/pull/4781
This improves legibility of labels that follow lines in pitched views.
The previous approach used the limited information in the shader to
calculate put the glyph in approximatelyright place. The new approach
does this more accurately by doing it on the cpu where we have access to
the entire line geometry.
- puts function definitions in a namespace ... {} rather than using namespace ...;
- remove trailing whitespace
- add trailing newline
- protect SQL statements from being formatted by clang-format
