Run ranlib on libvpx.a after install

libvpx strips it, which mangles the symbol index when LTO is enabled.
ranlib fixes it again.

scripts.d/50-libvpx.sh

@@ -51,6 +51,9 @@ ffbuild_dockerbuild() {
     ./configure "${myconf[@]}"
     make -j$(nproc)
     make install
+
+    # Work around strip breaking LTO symbol index
+    "$RANLIB" "$FFBUILD_PREFIX"/lib/libvpx.a
 }
 
 ffbuild_configure() {