I went to compile a project of mine, which uses SDL, SDL_ttf, OpenAL, and GTK. All of which are outputting errors like the following:
TxtFunc.cpp:(.text+0x61
Generally you need to have your -l options after the files that use the symbols on the command line. Perhaps try moving the sdl-config --libs --cflags to the end of the command? i.e. for your test program:
sdl-config --libs --cflags
g++ -o sdl-test ./sdl-test.cpp `sdl-config --libs --cflags`