merge pixman 0.46.4.

initial import of pixman-0.46.4

un-merge pixman 0.42.2 and re-merge 0.38.4.

initial import of revert to pixman-0.38.4.

see arm64 neon issues, and other issues (eg, PR#57108)

initial import of pixman-0.42.2

initial import of pixman-0.38.4

initial import of pixman-0.38.0

initial import of pixman-0.36.0

initial import of pixman-0.34.0

initial import of pixman-0.32.6

initial import of pixman-0.32.4

initial import of pixman-0.30.0

initial import of pixman-0.28.2

initial import of pixman-0.23.2. important changes include:
- more SSE2 support
- more arm neon and A8 support
- several bug fixes