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

ports/toybox/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.
 
 EXECUTABLES="toybox"
 
 # Toybox wants to build in its current directory.
 BUILD_DIR=${SRC_DIR}
 
 NACLPORTS_CPPFLAGS+=" -DBYTE_ORDER=LITTLE_ENDIAN"
-NACLPORTS_CPPFLAGS+=" -Dmain=nacl_main"
 NACLPORTS_CPPFLAGS+=" -Dpipe=nacl_spawn_pipe"
-NACLPORTS_LDFLAGS+=" ${NACL_CLI_MAIN_LIB}"
 
 export HOSTCC=cc
 
+EnableCliMain
 EnableGlibcCompat
 
-NACLPORTS_LDFLAGS+=" -l${NACL_CXX_LIB}"
-
 ConfigureStep() {
   LogExecute cp ${START_DIR}/toybox.config ${SRC_DIR}/.config
 }
 
 BuildStep() {
   # We can't use NACL_CROSS_PREFIX without also redefining the CC and HOSTCC
   # variables.
   if [[ "${NACLCC}" = *clang ]]; then
     CC=clang
   else
     CC=gcc
   fi
 
   export CROSS_COMPILE="${NACL_CROSS_PREFIX}-"
   export LDFLAGS="${NACLPORTS_LDFLAGS}"
   export CFLAGS="${NACLPORTS_CPPFLAGS} ${NACLPORTS_CFLAGS}"
+  export LIBS="${NACLPORTS_LIBS}"
   export CC
   LogExecute make clean
   DefaultBuildStep
 }
 
 InstallStep() {
   MakeDir ${PUBLISH_DIR}
   local ASSEMBLY_DIR="${PUBLISH_DIR}/toybox"
   MakeDir ${ASSEMBLY_DIR}
 
   cp ${BUILD_DIR}/toybox ${ASSEMBLY_DIR}/toybox_${NACL_ARCH}${NACL_EXEEXT}
 
   ChangeDir ${ASSEMBLY_DIR}
   LogExecute python ${NACL_SDK_ROOT}/tools/create_nmf.py \
       ${ASSEMBLY_DIR}/toybox_*${NACL_EXEEXT} \
       -s . \
       -o toybox.nmf
   LogExecute python ${TOOLS_DIR}/create_term.py toybox.nmf
 
   InstallNaClTerm ${ASSEMBLY_DIR}
   LogExecute cp ${START_DIR}/manifest.json ${ASSEMBLY_DIR}
   LogExecute cp ${START_DIR}/icon_16.png ${ASSEMBLY_DIR}
   LogExecute cp ${START_DIR}/icon_48.png ${ASSEMBLY_DIR}
   LogExecute cp ${START_DIR}/icon_128.png ${ASSEMBLY_DIR}
   ChangeDir ${PUBLISH_DIR}
   CreateWebStoreZip toybox-${VERSION}.zip toybox
 }