diff --git a/configure.in b/configure.in
index 20f68e704..1f535d978 100644
--- a/configure.in
+++ b/configure.in
@@ -280,6 +280,10 @@ dnl
                "$FLAC_LIBS")
   if test "$flac_found" = "yes"; then
     AC_CHECK_HEADERS(FLAC/format.h, , flac_found=no)
+  else
+    echo '*** WARNING:'
+    echo '*** libflac was not found. mkvmerge will be built'
+    echo '*** without support for FLAC tracks.'
   fi
 
 AC_SUBST(FLAC_LIBS)