[mod_av] Update error message

Five years ago, commit b29174e added the scale/conversion library of
FFmpeg. However, that library is not part of libavformat-dev and added
an additional requirement. That was not reflected in the error message,
when FFmpeg libraries are missing.

diff --git a/src/mod/applications/mod_av/Makefile.am b/src/mod/applications/mod_av/Makefile.am
index e697d9ec930fa795f4a747e968600a844603b6b2..ebf4c9392993172f3d999a9236ae522d6ea5b8e9 100644 (file)
--- a/src/mod/applications/mod_av/Makefile.am
+++ b/src/mod/applications/mod_av/Makefile.am
@@ -36,5 +36,5 @@ else
 install: error
 all: error
 error:
-       $(error You must install libavformat-dev to build mod_av)
+       $(error You must install libavformat-dev and libswscale-dev to build mod_av)
 endif