and remove "release" from the enum tag names.
no functional change, however, despite the addition of
backwards-compatibile declarations in this patch, it is breaking because
expressions that use `==` or `!=` operators will not able to use the
deprecated names.
I predict these names to survive until the 1.0 tag without any more
breakage.
Instead of padding, use static entropy to detect corrupted header.
* 64-bit, safe modes: 10 canary bits
* 64-bit, unsafe modes: 0 canary bits
* 32-bit: 27 canary bits
A further enhancement, not done here, would be to upgrade from canary to
parity.
These functions can only be exported when external libc components are
available due to the errno location dependency. Note that even when zig
libc is complete, on Windows, errno location will always be external (in
ucrtbase.dll).