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

ports/samba/build.sh

 #!/bin/bash
 # Copyright (c) 2015 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.
 
 # Samba doesn't seem to support building outside the source tree.
 BUILD_DIR=${SRC_DIR}
 
-#NACLPORTS_CPPFLAGS+=" -Dmain=nacl_main"
-
 #NACLPORTS_LDFLAGS+="${NACL_CLI_MAIN_LIB}"
 
 EnableGlibcCompat
 
 ConfigureStep() {
   conf_build=$(/bin/sh "${SCRIPT_DIR}/config.guess")
 
   SetupCrossEnvironment
 
   local CONFIGURE=${NACL_CONFIGURE_PATH:-${SRC_DIR}/configure}
@@ skipping 77 matching lines @@
   LogExecute ln -sf libwind-samba4.so libwind-samba4.so.0
   LogExecute ln -sf libtevent.so libtevent.so.0
   LogExecute ln -sf libgssapi-samba4.so libgssapi-samba4.so.2
   LogExecute ln -sf libhcrypto-samba4.so libhcrypto-samba4.so.5
   LogExecute ln -sf libheimbase-samba4.so libheimbase-samba4.so.1
   LogExecute ln -sf libndr-krb5pac.so libndr-krb5pac.so.0
   LogExecute ln -sf libtevent-util.so libtevent-util.so.0
   LogExecute ln -sf libsamba-credentials.so libsamba-credentials.so.0
   LogExecute ln -sf libsamba-hostconfig.so libsamba-hostconfig.so.0
 }