post_modules/SDL/configure.in in 7.4 contains this oddity:
if test x"$pike_cv_sys_os" = xWindows_NT ; then enable_sdltest=no fi
It causes builds to fail completely on NT systems that doesn't have SDL installed (e.g. http://pike.ida.liu.se/development/pikefarm/ result.xml?id=123_15&pike=7_4). If the SDL test doesn't work for some reason, isn't it better to give --disable-sdltest on the specific systems where it's known to be installed?