Remove mention to AVIF_LOCAL for codecs. (#1795)

README.md

@@ -51,10 +51,10 @@ and rav1e uses cargo (Rust). Check each library's documentation for an exact
 list of requirements.
 
 If you want to statically link any codec into your local (static) build of
-libavif, building using one of these scripts and then enabling the associated
-`AVIF_LOCAL_*` and setting `AVIF_CODEC_*` to `LOCAL` is a convenient method,
-but you must make sure to disable `BUILD_SHARED_LIBS` in CMake to instruct it
-to make a static libavif library.
+libavif, building using one of these scripts and then setting the associated
+`AVIF_CODEC_*` to `LOCAL` is a convenient method, but you must make sure to
+disable `BUILD_SHARED_LIBS` in CMake to instruct it to make a static libavif
+library.
 
 If you want to build/install shared libraries for AV1 codecs, you can still
 peek inside of each script to see where the current known-good SHA is for each