Avoid building and archiving the x86-64 pnacl-sz.nexe.

pnacl/build.sh

 #!/bin/bash
 # Copyright (c) 2012 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.
 #
 #@                 PNaCl toolchain build script
 #@-------------------------------------------------------------------
 #@ This script builds the ARM and PNaCl untrusted toolchains.
 #@ It MUST be run from the native_client/ directory.
 ######################################################################
@@ skipping 378 matching lines @@
   local tools="pnacl-llc"
   if [[ "${arch}" == "i686" ]]; then
     tools+=" pnacl-sz"
   fi
   for toolname in ${tools}; do
     cp -f "${objdir}"/Release*/bin/${toolname} .
     mv -f ${toolname} ${toolname}.pexe
     local arches=${arch}
     if [[ "${arch}" == "universal" ]]; then
       arches="${SBTC_ARCHES_ALL}"
-    elif [[ "${arch}" == "i686" ]]; then
+    elif [[ "${arch}" == "i686" && "${toolname}" == "pnacl-llc" ]]; then
       # LLVM does not separate the i686 and x86_64 backends.
-      # Translate twice to get both nexes.
+      # Translate twice to get both nexes, but only for pnacl-llc.
+      # We do not yet have an x86-64 backend for pnacl-sz.
       arches="i686 x86_64"
     fi
     local have_segment_gap="false"
     if [ "${toolname}" == "pnacl-sz" ]; then
       have_segment_gap="true"
     fi
     translate-sb-tool ${toolname} "${arches}" "${have_segment_gap}"
     install-sb-tool ${toolname} "${arches}"
   done
   spopd
@@ skipping 603 matching lines @@
 
 if [ "$(type -t $1)" != "function" ]; then
   #Usage
   echo "ERROR: unknown function '$1'." >&2
   echo "For help, try:"
   echo "    $0 help"
   exit 1
 fi
 
 "$@"