The gcc-win32 build pages have been split into three areas:

• Native win32 build environment, using Cygwin:
  http://www.libsdl.org/extras/win32/cygwin/README.txt
• Native win32 build environment, using MinGW:
  http://www.libsdl.org/extras/win32/mingw32/README.txt
• Cross-compiled win32 build environment under Linux:
  http://www.libsdl.org/extras/win32/cross/README.txt