Add support for new pnacl native toolchain driver

ports/ffmpeg/nacl.patch

+diff --git a/Makefile b/Makefile
+--- a/Makefile
++++ b/Makefile
+@@ -116,7 +116,9 @@ ffprobe.o cmdutils.o libavcodec/utils.o libavformat/utils.o libavdevice/avdevice
+ 
+ $(PROGS): %$(PROGSSUF)$(EXESUF): %$(PROGSSUF)_g$(EXESUF)
+        $(CP) $< $@
+-       $(STRIP) $@
++       -if test "$(NACL_ARCH)" != "le32"; then \
++               $(STRIP) $@; \
++       fi
+ 
+ %$(PROGSSUF)_g$(EXESUF): %.o $(FF_DEP_LIBS)
+        $(LD) $(LDFLAGS) $(LDEXEFLAGS) $(LD_O) $(OBJS-$*) $(FF_EXTRALIBS)
 diff --git a/configure b/configure
 --- a/configure
 +++ b/configure
+@@ -2719,7 +2719,7 @@ ln_s="ln -s -f"
+ nm_default="nm -g"
+ objformat="elf"
+ pkg_config_default=pkg-config
+-if ranlib 2>&1 | grep -q "\-D "; then
++if [ $NACL_ARCH != le32 ] && ranlib 2>&1 | grep -q "\-D "; then
+     ranlib_default="ranlib -D"
+ else
+     ranlib_default="ranlib"
 @@ -4761,7 +4761,13 @@ if ! disabled network; then
  fi
  
  check_builtin atomic_cas_ptr atomic.h "void **ptr; void *oldval, *newval; atomic_cas_ptr(ptr, oldval, newval)"
 -check_builtin atomic_compare_exchange "" "int *ptr, *oldval; int newval; __atomic_compare_exchange_n(ptr, oldval, newval, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)"
 +# Check for both __atomic_compare_exchange_n and __atomic_add_fetch since
 +# HAVE_ATOMIC_COMPARE_EXCHANGE should only be defined if both are present.
 +# Currently PNaCl supports __atomic_compare_exchange_n but not
 +# __atomic_add_fetch so testing for __atomic_compare_exchange_n was not
 +# enough.
@@ skipping 16 matching lines @@
      getrusage(RUSAGE_SELF, &rusage);
 @@ -3955,7 +3955,7 @@ static int64_t getutime(void)
  
  static int64_t getmaxrss(void)
  {
 -#if HAVE_GETRUSAGE && HAVE_STRUCT_RUSAGE_RU_MAXRSS
 +#if HAVE_GETRUSAGE && HAVE_STRUCT_RUSAGE_RU_MAXRSS && !defined(__native_client__)
      struct rusage rusage;
      getrusage(RUSAGE_SELF, &rusage);
      return (int64_t)rusage.ru_maxrss * 1024;