Expose wait4 as wait4 rather than __wait4.

This helps strace(1) compile with one fewer hack.

Change-Id: I5296d0cfec5546709cda990abd705ad33d7c4626
Merge "Expose wait4 as wait4 rather than __wait4."
Provide glibc-compatible SYS_* aliases for the __NR_* constants.

This helps us remove another external/strace bionic hack.

Change-Id: I3e82c0d2fd27e479be98f096e05b666fd16f8eb3
Merge "Provide glibc-compatible SYS_* aliases for the __NR_* constants."
Merge remote-tracking branch 'aosp/master'