Add support for new pnacl native toolchain driver

ports/imagemagick/build.sh

 # Copyright (c) 2011 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.
-
+NACLPORTS_CPPFLAGS+=" ${NACL_EXCEPTIONS_FLAG}"
 if [ "${NACL_LIBC}" = "newlib" ]; then
   # TODO(sbc): remove once this is fixed:
   # https://code.google.com/p/nativeclient/issues/detail?id=3790
   NACLPORTS_CPPFLAGS+=" -DSSIZE_MAX=LONG_MAX"
   EXE_DIR=""
 else
   EXE_DIR=".libs/"
 fi
 
 EXTRA_CONFIGURE_ARGS="
@@ skipping 55 matching lines @@
   # The tests as (a) very slow and (b) not all passing at this point.
   return 0
 
   # As part of 'make check' there will be several test executables built.
   # We need to create the script that launch them ahead of time.
   for EXE in ${TEST_EXECUTABLES}; do
     WriteLauncherScript ${EXE%%${NACL_EXEEXT}} $(basename ${EXE})
   done
   LogExecute make check
 }