Okay, Atmel does not call it this way, but I now will.
Downloaded the bundle from http://distribute.atmel.no/tools... (a whopping 265MB) .
I am not interested in the diluted stuff, so I haven't install it as intended. It is a normal zip, thanks heavens, so instead I found the fairly standard WinAVR installation within it, under as4e-ide\plugins\com.atmel.avr.toolchains.win32.x86_184.108.40.206007011157\os\win32\. Unzipped to a suitable directory (say, WinAVR20100701).
Running [WinAVR20100701]/bin/avr-gcc.exe on a .c source ends with cc1.exe complaining of missing libgmp-3.dll. This .dll is in [WinAVR20100701]/bin/ (whereas cc1.exe is in [WinAVR20100701]/libexec/gcc/avr/4.4.3/). Okay I did not properly install, paths are missing - added a path to [WinAVR20100701]/bin/, but that did not help. I am not good in the Win path games, so I gave up and simply copied libgmp-3.dll (and libmpfr-1.dll which also appears to be needed) into [WinAVR20100701]/libexec/gcc/avr/4.4.3/ . That did the trick - now it appears I can compile.
avr-gcc (atmel-201007011147CEST-(mingw32_special)) 4.4.3
and avr-libc is of course 1.7.0.
I played a bit compiling simple examples I have here and everything appears to work.