Defines in moz.build do not propagate to subdirs. libjpegturbo 3.0.x compiled the 8 bit variation of the files via the main moz.build, and the 12 bit and 16 bit variations were compiled in subdirs for each of those bit depths. This meant we probably lost simd when compiling 12 and 16 bit files. When we moved to libjpegturbo 3.1.x all bit depths got moved to the wrapper subdir and compiled there, so we then lost simd when compiling the 8 bit depth too.
Have a common moz.build to include in all subdir moz.build to fix it.
Differential Revision: https://phabricator.services.mozilla.com/D298504
Timothy Nikkel
d9dae2557f