diff --git a/tools/README.txt b/tools/README.txt
index 55140d7fad..44b0427427 100644
--- a/tools/README.txt
+++ b/tools/README.txt
@@ -135,6 +135,12 @@ mkexport.sh and Makefile.export
   Makefile.export is used only by the mkexport.sh script to parse out
   options from the top-level Make.defs file.
 
+  USAGE: tools/mkexport.sh [-d] [-z] [-u] [-w|wy|wn] -t <top-dir> [-x <lib-ext>] -l "lib1 [lib2 [lib3 ...]]"
+
+  Thais script also depends on the environment variable MAKE which is set
+  in the top-level Makefile before starting mkexport.sh.  If MAKE is not
+  defined, the script will set it to `which make`.
+
 mkfsdata.pl
 -----------
 
diff --git a/tools/mkexport.sh b/tools/mkexport.sh
index ebaff91b88..348a14cf5c 100755
--- a/tools/mkexport.sh
+++ b/tools/mkexport.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 # tools/mkexport.sh
 #
-#   Copyright (C) 2011-2012, 2014 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2011-2012, 2014, 2016 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -115,6 +115,12 @@ if [ ! -f "${TOPDIR}/.version" ]; then
 	exit 1
 fi
 
+# Check if the make environment variable has been defined
+
+if [ -z "${MAKE}" ]; then
+	MAKE=`which make`
+fi
+
 # Get the version string
 
 source "${TOPDIR}/.version"