diff --git a/src/toolcheck b/src/toolcheck
new file mode 100755
index 0000000..b05118a
--- /dev/null
+++ b/src/toolcheck
@@ -0,0 +1,36 @@
+#!/bin/sh
+# toolcheck -- check for tools that have severe bugs. Good that all the buggy
+#	       tools identify by version numbers. This is the spirit of GNU :-)
+#
+# 24.7.95 jw.
+
+retval=0
+reply="`sh -version -c exit 2>&1 < /dev/null`"
+case "$reply" in
+	GNU*1.14.3*)
+		echo "- sh is	'$reply'";
+		echo "  CAUTION: This shell has a buggy 'trap' command.";
+		echo "           The configure script may fail silently.";
+		retval=1;
+		;;
+	GNU*)
+		echo "- sh is	'$reply' - probably OK.";
+		;;
+	*)	;;
+esac
+
+reply="`sed --version 2>&1 < /dev/null`"
+case "$reply" in
+	GNU\ sed\ version\ 2.0[34])
+		echo "- sed is	'$reply'";
+		echo "  CAUTION: This sed cannot configure screen properly."
+		retval=1;
+		;;
+	GNU\ sed\ version\ 2.05|GNU\ sed\ version\ 2.03\ kevin)
+		echo "- sed is	'$reply' - good.";
+		;;
+	GNU*)	echo "- sed is	'$reply'.";
+		;;
+	*)	;;
+esac
+exit $retval