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

ports/xorg-server/build.sh

 #!/bin/bash
 # 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.
 
 NACLPORTS_CPPFLAGS+=" -I${NACLPORTS_INCLUDE}/pixman-1"
 NACLPORTS_CPPFLAGS+=" -DFASYNC=O_NONBLOCK -DFNDELAY=O_NONBLOCK"
 
 EXECUTABLES=hw/kdrive/sdl/Xsdl${NACL_EXEEXT}
 
@@ skipping 15 matching lines @@
 
 if [ "${NACL_LIBC}" = "newlib" ]; then
   EXTRA_CONFIGURE_ARGS+=" --enable-xvfb=no"
   EXTRA_CONFIGURE_ARGS+=" --enable-xorg=no"
 fi
 
 NACLPORTS_CPPFLAGS+=" -Dmain=SDL_main"
 export LIBS="\
 ${NACL_CLI_MAIN_LIB} \
 -Wl,--undefined=SDL_main \
--Wl,--undefined=nacl_main \
 -Wl,--undefined=nacl_startup_untar \
 -lSDLmain -lSDL -lRegal -lglslopt -lppapi_gles2 -lm \
 -l${NACL_CXX_LIB}"
 
 PatchStep() {
   DefaultPatchStep
   MakeDir ${SRC_DIR}/hw/kdrive/sdl
   LogExecute cp ${START_DIR}/sdl.c \
                 ${START_DIR}/Makefile.am \
                 ${SRC_DIR}/hw/kdrive/sdl/
@@ skipping 54 matching lines @@
   LogExecute tar cvf ${ASSEMBLY_DIR}/xorg-xkb.tar share/X11/xkb
   LogExecute shasum ${ASSEMBLY_DIR}/xorg-xkb.tar > \
       ${ASSEMBLY_DIR}/xorg-xkb.tar.hash
   local XFONTS_DIR=${NACL_PACKAGES_PUBLISH}/xfonts/${TOOLCHAIN}
   LogExecute cp ${XFONTS_DIR}/xorg-fonts.tar ${ASSEMBLY_DIR}/
   LogExecute cp ${XFONTS_DIR}/xorg-fonts.tar.hash ${ASSEMBLY_DIR}/
 
   ChangeDir ${PUBLISH_DIR}
   LogExecute zip -r xorg-server.zip xorg-server
 }