Reworked `SimulatedClassPool >> #associationAt:ifAbsent:` to throw an error
...if there's no such class variable. This makes it behave more like
dictionary / pool.
@REM -------
@REM make using mingw gnu compiler
@REM type mingwmake, and wait...
@REM do not edit - automatically generated from ProjectDefinition
@REM -------
@SET DEFINES=
@pushd ..\rules
@call find_mingw.bat
@popd
make.exe -N -f bc.mak %DEFINES% %USEMINGW_ARG% %*