Replace `ifNil:[...]` with `isNil ifTrue:[...]`
The latter is optimized by compilers and therefore faster.
@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% %*