A problem when install QT4.8.2 about w32api

When I upgrade qt to 4.8.2 version, It ask me to choose the path where minGW was installed, then it prompt that "only versions with W32API 3.13 are supported".
So I find w32api-3.13-mingw32-dev.tar, after unzip it then override some files in minGW installation directory, then QT installation go through.
Who can tell me what is the relationship between w32-api-ming32 and minGW.
What minGW is used to do?
waht w32api was used to do?
Thanks a lot.

MingW provides a Gnu GCC compiler and toolchain on Windows. The Win32 API component of MingW provides the necessary headers and support libraries to allow native Windows application to be built using MingW.