[Bug 45435] Fatal error compiling on Fedora 28 because libavcodec file not found

https://bugs.winehq.org/show_bug.cgi?id=45435

--- Comment #8 from Yasser  ---
After some time seeing the makefiles generated, i've found that manually add
-I/usr/include/ffmpeg on all xapofx1_* fixes the compile error but causes
another problem, i dont know how to debug this sorry.

./../tools/widl/widl -o xaudio_classes_r.res -m64 -I.
-I../../../wine-git/dlls/xaudio2_7 -I../../include \
  -I../../../wine-git/include -I/usr/include/ffmpeg -D__WINESRC__ -lavcodec
-lavutil -DXAUDIO2_VER=7 \
  ../../../wine-git/dlls/xaudio2_7/xaudio_classes.idl
../../tools/widl/widl: unrecognized option '-lavcodec'
Usage: widl [options...] infile.idl