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

build/libass.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -euo pipefail
+
+CONF_FLAGS=(
+  --prefix=$INSTALL_DIR                               # install library in a build directory for FFmpeg to include
+  --host=i686-gnu                                     # use i686 linux
+  --disable-shared
+  --enable-static
+  --disable-asm                                       # disable asm optimization
+  --disable-fontconfig
+  --disable-require-system-font-provider
+)
+
+./autogen.sh && emconfigure ./configure "${CONF_FLAGS[@]}"
+emmake make install -j