Hi liqi,
Sorry I'm not sure I understand your question.
At the moment, the Win32 installer is only available for version 0.43 of Ecere
(Which is rather outdated, especially since it doesn't understand the new project file format (epj)). We're hoping to update that in a relatively near future.
The MinGW that is packaged with it is a collection of official MinGW binary packages, the GCC version included is:
gcc (GCC) 4.3.0 20080305 (alpha-testing) mingw-20080502
The 0.43 installer does also include UPX which can be used to compress executables to a smaller size, and I think it has that extra GL/glext.h header as well.
Also, in that installer mingw32-make.exe is renamed to make.exe (which is not standard on MinGW, because it can conflict with other make programs).
You should change it back or copy it to mingw32-make.exe if you are using the 0.44 candidate versions of Ecere.
You can use any MinGW version along with Ecere, but your mileage may vary depending on the versions. (I've encountered various GCC bugs in the newer GCC 4 versions, sometimes tried to work around or report them on MinGW and GCC mailing lists). I used both the GCC version of that installer (4.3.0 20080305 (alpha-testing)) as well as 4.4.0 with a certain amount of success.
Cheers,
Jerome