Add support for new pnacl native toolchain driver

ports/ffmpeg/build.sh

 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 EXECUTABLES="ffmpeg ffmpeg_g ffprobe ffprobe_g"
 
 # needed for RLIMIT_CPU
 EnableGlibcCompat
 
 ConfigureStep() {
 
   SetupCrossEnvironment
 
   local extra_args=""
-  if [ "${TOOLCHAIN}" = "pnacl" ]; then
+  if [ "${TOOLCHAIN}" = "pnacl" -a "${NACL_ARCH}" != "le32" ]; then
     extra_args="--cc=pnacl-clang"
+  elif [ "${TOOLCHAIN}" = "pnacl" -a "${NACL_ARCH}" = "le32" ]; then
+    extra_args="--cc=${CC}"
   elif [ "${TOOLCHAIN}" = "clang-newlib" ]; then
     extra_args="--cc=${CC}"
   fi
 
-  if [ "${NACL_ARCH}" = "pnacl" ]; then
+  if [ "${NACL_ARCH}" = "pnacl" -o "${NACL_ARCH}" = "le32" ]; then
     extra_args+=" --arch=pnacl"
   elif [ "${NACL_ARCH}" = "arm" ]; then
     extra_args+=" --arch=arm"
   else
     extra_args+=" --arch=x86"
   fi
 
   LogExecute ${SRC_DIR}/configure \
     --cross-prefix=${NACL_CROSS_PREFIX}- \
     --target-os=linux \
@@ skipping 15 matching lines @@
     --disable-demuxer=rtsp \
     --disable-demuxer=image2 \
     --prefix=${PREFIX} \
     ${extra_args}
 }
 
 TestStep() {
   SetupCrossPaths
   LogExecute make testprogs
 }