add a minimal setup check to Makefile, also print a notice to users running the developer makefile on other than Linux platforms

Makefile

@@ -170,7 +170,11 @@ CCLIBS += -lncurses  # on some systems -lreadline also requires -lncurses (e.g.
 
 # Compile 'duk' only by default
 .PHONY:	all
-all:	duk
+all:	checksetup duk
+
+.PHONY: checksetup
+checksetup:
+	@util/check_setup.sh
 
 .PHONY:	clean
 clean:

util/check_setup.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+#
+#  Check prerequisites for using the Duktape makefile.  Exit with an error
+#  and a useful error message for missing prerequisites.
+#
+
+NODE_VERSION=`node -v 2>/dev/null`
+if [ "x$NODE_VERSION" = "x" ]; then
+	echo "*** Missing NodeJS:"
+	echo "  $ sudo apt-get install nodejs npm"
+	exit 1
+fi
+
+GIT_VERSION=`git --version`
+if [ "x$GIT_VERSION" = "x" ]; then
+	echo "*** Missing git:"
+	echo "  $ sudo apt-get install git"
+	exit 1
+fi
+
+uname -a | grep -ni linux >/dev/null
+RET=$?
+if [ "x$RET" != "x0" ]; then
+	echo "*** Based on uname, you're not running on Linux.  Duktape developer"
+	echo "    makefile is intended for Linux only; YMMV on other platforms."
+	echo ""
+	sleep 1
+fi