The changelog.
Here is a summary of the amount of change made since the original mawk 1.3.3.
Besides the gamut of *nix systems (including the Cygwin layer in Windows), I have built this with Visual Studio also. Here are binaries:
As noted, mawk has been neglected by some packagers (see for example this). For that reason, the list is presented in two parts. There are, by the way, various rpm and dpkg packages in my ftp area which you may find useful.
Current:
Older:
You should report bugs to me.