Any Android specific modifications to upstream libjpeg-turbo (the version
specified in METADATA) should be listed here:

(1) jconfig.h and jconfigint.h

These are included upstream as jconfig.h.in and jconfigint.h.in.
We have the option autogenerate these platform/version specific files (using
the libjpeg-turbo build system) or to manually create them.

Autogenerating these files on linux gets us most of the way, but we've needed
to add some multi-platform flexibility to the INLINE and SIZEOF_SIZE_T macros.

(2) simd/arm64/jsimd_neon.S

To support execute-only memory layouts, constants in handwritten assembly have
been moved into a dedicated rodata section.

There's a pull request upstream for this as well. If that's accepted, this
can be removed as an Android-specific modification.
https://github.com/libjpeg-turbo/libjpeg-turbo/pull/318