lines 204 and 210 of Ecore_Audio.h, there is a #if with macro set by efl's configure. This is wrong for a public header and forbid any compilation of programs using ecore_audio
one solution : if there is only 2 cases (wasapi on windows and pulseaudio everywhere else), then a #ifdef _WIN32 / #else / #endif check would be possible
otherwise, doing like elm does is possible too (elm is having Elementary.h.in, with macro set by configure at the top)
Anyway, wasapi is always usable on Windows, so a #if _WIN32 on this platform is always possible line 210 and I would do that