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

ports/python/build.sh

 # Copyright (c) 2013 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=python${NACL_EXEEXT}
 
-NACLPORTS_CPPFLAGS+=" -Dmain=nacl_main"
-
 # This build relies on certain host binaries and python's configure
 # requires us to set --build= as well as --host=.
 HOST_BUILD_DIR=${WORK_DIR}/build_host
 
 # Workaround for arm-gcc bug:
 # https://code.google.com/p/nativeclient/issues/detail?id=3205
 # TODO(sbc): remove this once the issue is fixed
 if [ "${NACL_ARCH}" = "arm" ]; then
   NACLPORTS_CPPFLAGS+=" -mfpu=vfp"
 fi
@@ skipping 12 matching lines @@
   # Disable ipv6 since configure claims it requires a working getaddrinfo
   # which we do not provide.  TODO(sbc): remove this once nacl_io supports
   # getaddrinfo.
   EXTRA_CONFIGURE_ARGS+=" --disable-ipv6"
   EXTRA_CONFIGURE_ARGS+=" --with-suffix=${NACL_EXEEXT}"
   EXTRA_CONFIGURE_ARGS+=" --build=x86_64-linux-gnu"
   if [ "${NACL_DEBUG}" = 1 ]; then
     EXTRA_CONFIGURE_ARGS+=" --with-pydebug"
   fi
   NACLPORTS_LIBS+=" -ltermcap"
-  NACLPORTS_LIBS+=" ${NACL_CLI_MAIN_LIB}"
   if [ "${NACL_LIBC}" = "newlib" ]; then
     # When python builds with wait3/wait4 support it also expects struct rusage
     # to have certain fields and newlib lacks.
     export ac_cv_func_wait3=no
     export ac_cv_func_wait4=no
   fi
+  EnableCliMain
   EnableGlibcCompat
   DefaultConfigureStep
   if [ "${NACL_LIBC}" = "newlib" ]; then
     # For static linking we copy in a pre-baked Setup.local
     LogExecute cp ${START_DIR}/Setup.local Modules/
   fi
 }
 
 BuildStep() {
   export CROSS_COMPILE=true
@@ skipping 55 matching lines @@
   InstallNaClTerm ${assembly_dir}
   LogExecute cp ${START_DIR}/background.js ${assembly_dir}
   LogExecute cp ${START_DIR}/python.js ${assembly_dir}
   LogExecute cp ${START_DIR}/index.html ${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 python.zip .
 }