Problem linking with SDL_gfx

I’m trying to compile a test program using SDL_gfx under MinGW, but I
get errors like this:

undefined reference to `_imp__aalineColor’

Anytime I use a function from SDL_gfx, “imp_” is prepended to its name
and then it can’t be found. I get the same error with the test programs
included with SDL_gfx.

I compiled SDL_gfx under MSYS with “./configure && make && make
install”, and I am linking my test program with “-lmingw32 -lSDLmain
-lSDL -lSDL_gfx”. I have no problem with using any functions from plain
SDL, SDL_mixer or SDL_image.

Thanks for any suggestions,