Switch from using 'nacl_main' to 'main' entry point

ports/binutils/build.sh

 # Copyright (c) 2014 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.
 
 export ac_cv_func_getrlimit=no
 
-export EXTRA_LIBS="${NACL_CLI_MAIN_LIB}"
+EnableCliMain
+
 EXTRA_CONFIGURE_ARGS="\
   --enable-targets=x86_64-nacl,arm-nacl,avr \
   --disable-werror \
   --enable-deterministic-archives \
   --without-zlib"
 
 BuildStep() {
   export CONFIG_SITE
   DefaultBuildStep
 }
 
 InstallStep() {
   DefaultInstallStep
 
   # The ldscripts that ship with this verion of binutils doesn't seem to
   # work with the glibc toolchain devenv.  Instead we copy the linker scripts
   # out of the SDK root.
   rm -rf ${DESTDIR}${PREFIX}/${NACL_ARCH}-nacl/lib/ldscripts
   LogExecute cp -r \
    ${NACL_SDK_ROOT}/toolchain/${OS_SUBDIR}_x86_glibc/x86_64-nacl/lib/ldscripts \
    ${DESTDIR}${PREFIX}/${NACL_ARCH}-nacl/lib/
 }