Merge changes from github.
Change: 137532946
diff --git a/util/python/python_config.sh b/util/python/python_config.sh
index 50f6398..8a780c8 100755
--- a/util/python/python_config.sh
+++ b/util/python/python_config.sh
@@ -113,29 +113,33 @@
     echo -e "\n\nERROR: Problem getting python include path.  Is distutils installed?"
     exit 1
   fi
-  local python_lib_path
-  # Split python_path into an array of paths, this allows path containing spaces
-  IFS=','
-  python_lib_path=($(python_path))
-  unset IFS
-  echo "Found possible Python library paths:"
-  for x in "${python_lib_path[@]}"; do
-    echo "  $x"
-  done
-  set -- "${python_lib_path[@]}"
-  echo "Please input the desired Python library path to use.  Default is ["$1"]"
-  read b || true
-  if [ "$b" == "" ]; then
-   python_lib="$(default_python_path "${python_lib_path[0]}")"
-   echo $python_lib
-  else
-    if test -d "$b" -a -x "$b"; then
-      python_lib="$b"
+
+  if [ -z "$PYTHON_LIB_PATH" ]; then
+    local python_lib_path
+    # Split python_path into an array of paths, this allows path containing spaces
+    IFS=','
+    python_lib_path=($(python_path))
+    unset IFS
+    echo "Found possible Python library paths:"
+    for x in "${python_lib_path[@]}"; do
+      echo "  $x"
+    done
+    set -- "${python_lib_path[@]}"
+    echo "Please input the desired Python library path to use.  Default is ["$1"]"
+    read b || true
+    if [ "$b" == "" ]; then
+      PYTHON_LIB_PATH="$(default_python_path "${python_lib_path[0]}")"
+      echo $PYTHON_LIB_PATH
     else
-      echo -e "\n\nERROR: The path you have entered does not exist."
-      exit 1
+      PYTHON_LIB_PATH="$b"
     fi
   fi
+  if test -d "$PYTHON_LIB_PATH" -a -x "$PYTHON_LIB_PATH"; then
+    python_lib="$PYTHON_LIB_PATH"
+  else
+    echo -e "\n\nERROR: Invalid python library path: ${PYTHON_LIB_PATH}."
+    exit 1
+  fi
 
   local numpy_include=$("${PYTHON_BIN_PATH}" -c 'from __future__ import print_function; import numpy; print(numpy.get_include());')
   if [ "$numpy_include" == "" ]; then