The magic numbers that C defines are obnoxious. We had partial
definitions for these internally. Add the missing one and move them to
a public header for anyone else that may want to use them.
Bug: None
Test: None
Change-Id: Ia6b8cff4310bcccb23078c52216528db668ac966
This is undefined behavior, but glibc and macOS are both lenient, and
someone hit this in the wild, so we may as well be lenient too. (The
only cost is that it's now slightly easier to write code that works on
everything except old versions of Android.)
Bug: https://issuetracker.google.com/180598400
Test: treehugger
Change-Id: Ia217169ea6283cc53f4fbf71e5abfa08356c2049