Migrate all libs (remove fdk-aac due to license issue and wavpack as no longer supported)

build/opus.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+set -euo pipefail
+
+CONF_FLAGS=(
+  --prefix=$INSTALL_DIR                               # install library in a build directory for FFmpeg to include
+  --host=i686-gnu                                     # use i686 linux
+  --enable-shared=no                                  # not to build shared library
+  --disable-asm                                       # not to use asm
+  --disable-rtcd                                      # not to detect cpu capabilities
+  --disable-doc                                       # not to build docs
+  --disable-extra-programs                            # not to build demo and tests
+  --disable-stack-protector
+)
+
+emconfigure ./autogen.sh
+CFLAGS=$CFLAGS emconfigure ./configure "${CONF_FLAGS[@]}"
+emmake make install -j