-@url{http://avisynth.nl, AviSynth 2.6} for 32-bit builds and
-@url{http://avs-plus.net, AviSynth+ 0.1} for 32-bit and 64-bit builds.
-The necessary @file{avisynth_c.h} header is the variant in the @file{extras/}
-directory of the @url{https://www.videolan.org/developers/x264.html, x264}
-source tree. For convenience, this header is also available from a
-@url{https://github.com/qyot27/avisynth_headers, temporary repository}
-along with an installation routine.
+@url{http://avisynth.nl, AviSynth 2.6 RC1 or higher} for 32-bit builds and
+@url{http://avs-plus.net, AviSynth+ r1718 or higher} for 32-bit and 64-bit builds.
+@url{https://github.com/AviSynth/AviSynthPlus, AviSynth+'s git repository}
+provides a GNU-style Makefile which can install just the headers using
+@code{make install PREFIX=/install/prefix}.
+
+@float NOTE
+When using AviSynth+'s installed headers, the user must also pass
+the avisynth/ include directory to @code{--extra-cflags}. For example,
+if the PREFIX given to AviSynth+'s Makefile was /usr/i686-w64-mingw32,
+then the correct command would be
+@code{--extra-cflags="-I/usr/i686-w64-mingw32/include/avisynth"}.
+@end float