Add emscripten support to config.sub

build_tools/nacl-env.sh

 #!/bin/bash
 # 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.
 
 # Echo the environment variables need to to build/configure standard
 # GNU make/automake/configure projects.  e.g. CC, CXX, CFLAGS, etc.
 # The values for these variables are calculated based on the following
 # environment variables:
 #
@@ skipping 130 matching lines @@
   export NACL_ARCH_ALT=x86_32
 else
   export NACL_ARCH_ALT=${NACL_ARCH}
 fi
 
 # NACL_CROSS_PREFIX is the prefix of the executables in the
 # toolchain's "bin" directory. For example: i686-nacl-<toolname>.
 if [ ${NACL_ARCH} = "pnacl" ]; then
   NACL_CROSS_PREFIX=pnacl
 elif [ ${NACL_ARCH} = "emscripten" ]; then
-  NACL_CROSS_PREFIX=em
+  NACL_CROSS_PREFIX=emscripten
 else
   NACL_CROSS_PREFIX=${NACL_ARCH}-nacl
 fi
 
 export NACL_LIBC
 export NACL_ARCH
 export NACL_CROSS_PREFIX
 
 InitializeNaClGccToolchain() {
   if [ ${NACL_ARCH} = "arm" ]; then
@@ skipping 182 matching lines @@
       echo "export PATH=${NACL_PREFIX}/bin:\${PATH}:${NACL_BIN_PATH}"
       echo "export CPPFLAGS=\"${NACL_CPPFLAGS}\""
       echo "export ARFLAGS=\"${NACL_ARFLAGS}\""
       echo "export LDFLAGS=\"${NACL_LDFLAGS}\""
     else
       NaClEnvExport
       exec "$@"
     fi
   fi
 fi