Summary:
@public
Our usage of C++ bit fields has lead to quite some problems with different compiler setups. Problems include sign bits, alignment, etc.
Here we introduce a portable implementation as a variadic template, allowing the user to store a number of booleans and enums (defined with `YG_ENUM_SEQ_DECL`) in an unsigned integer type of their choice.
This will replace all usages of bit fields across the Yoga code base.
Differential Revision: D16647801
fbshipit-source-id: 230ffab500885a3ad662ea8f19e35a5e9357a563
