Update build-ffmpeg

Author: srubin

build-ffmpeg

@@ -4,7 +4,7 @@
 # LICENSE: https://github.com/markus-perl/ffmpeg-build-script/blob/master/LICENSE
 
 PROGNAME=$(basename "$0")
-VERSION=1.21.rc3
+VERSION=1.21.rc4
 CWD=$(pwd)
 PACKAGES="$CWD/packages"
 WORKSPACE="$CWD/workspace"
@@ -416,7 +416,7 @@ if build "av1"; then
 	execute make -j $MJOBS
 
 	if [[ "$OSTYPE" == "darwin"* ]]; then
-	  execute install_name_tool -id "${WORKSPACE}/lib/libaom.2.dylib" libaom.2.dylib
+	  execute install_name_tool -id "${WORKSPACE}/lib/libaom.2.dylib" libaom.2.0.0.dylib
 	fi
 
   execute make install
@@ -598,7 +598,7 @@ if build "snappy"; then
   execute make -j $MJOBS
 
   if [[ "$OSTYPE" == "darwin"* ]]; then
-	  execute install_name_tool -id "${WORKSPACE}/lib/libsnappy.1.dylib" libsnappy.1.dylib
+	  execute install_name_tool -id "${WORKSPACE}/lib/libsnappy.1.dylib" libsnappy.1.1.8.dylib
 	fi
 
   execute make install