Add top level build script for building packages.

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.
 #
 # To import these variables into your environment do:
 # $ . nacl_env.sh
@@ skipping 252 matching lines @@
 fi
 
 NACL_LDFLAGS="-L${NACL_SDK_LIBDIR}"
 NACL_CFLAGS="-I${NACL_SDK_ROOT}/include"
 NACL_CXXFLAGS="-I${NACL_SDK_ROOT}/include"
 
 if [ ${NACL_GLIBC} = "1" ]; then
   NACL_LDFLAGS+=" -Wl,-rpath-link=${NACL_SDK_LIBDIR}"
 fi
 
-if [ $# -gt 0 ]; then
-  if [ "$1" = '--print' ]; then
-    echo "export CC=${NACLCC}"
-    echo "export CXX=${NACLCXX}"
-    echo "export AR=${NACLAR}"
-    echo "export RANLIB=${NACLRANLIB}"
-    echo "export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig"
-    echo "export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}"
-    echo "export PATH=\${PATH}:${NACL_BIN_PATH}"
-    echo "export CFLAGS=\"${NACL_CFLAGS}\""
-    echo "export LDFLAGS=\"${NACL_LDFLAGS}\""
-  else
-    export CC=${NACLCC}
-    export CXX=${NACLCXX}
-    export AR=${NACLAR}
-    export RANLIB=${NACLRANLIB}
-    export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig
-    export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}
-    export PATH=${PATH}:${NACL_BIN_PATH}
-    export CFLAGS=${NACL_CFLAGS}
-    exec $@
+if [ -z "${NACL_ENV_IMPORT:-}" ]; then
+  if [ $# -gt 0 ]; then
+    if [ "$1" = '--print' ]; then
+      echo "export CC=${NACLCC}"
+      echo "export CXX=${NACLCXX}"
+      echo "export AR=${NACLAR}"
+      echo "export RANLIB=${NACLRANLIB}"
+      echo "export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig"
+      echo "export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}"
+      echo "export PATH=\${PATH}:${NACL_BIN_PATH}"
+      echo "export CFLAGS=\"${NACL_CFLAGS}\""
+      echo "export LDFLAGS=\"${NACL_LDFLAGS}\""
+    else
+      export CC=${NACLCC}
+      export CXX=${NACLCXX}
+      export AR=${NACLAR}
+      export RANLIB=${NACLRANLIB}
+      export PKG_CONFIG_PATH=${NACLPORTS_LIBDIR}/pkgconfig
+      export PKG_CONFIG_LIBDIR=${NACLPORTS_LIBDIR}
+      export PATH=${PATH}:${NACL_BIN_PATH}
+      export CFLAGS=${NACL_CFLAGS}
+      exec $@
+    fi
   fi
 fi