diff -r 433497578ae1 src/make.bash
--- a/src/make.bash	Tue Nov 10 17:39:01 2009 -0800
+++ b/src/make.bash	Tue Nov 10 21:49:40 2009 -0500
@@ -7,12 +7,68 @@
 GOBIN="${GOBIN:-$HOME/bin}"
 export MAKEFLAGS=-j4
 
+RTFM_MSG="see http://golang.org/doc/install.html section 'Environment Variables' for details"
+
 if ! test -f $GOROOT/include/u.h
 then
 	echo '$GOROOT is not set correctly or not exported' 1>&2
 	exit 1
 fi
 
+if [ -e $GOBIN ]
+then
+	echo "$GOBIN is empty"
+	echo $RTFM_MSG
+	exit 1
+else
+	if [ ! -d $GOBIN ]
+	then
+		echo "$GOBIN references a directory that does not exist"
+		echo $RTFM_MSG
+		exit 1
+	fi
+fi
+
+if [ -e $GOARCH ]
+then
+	echo 'GOARCH is empty'
+	echo $RTFM_MSG
+	exit 1
+else
+	case "$GOARCH" in
+		amd64)
+			;;
+		386)
+			;;
+		arm)
+			;;
+		*)
+			echo "GOARCH must be one of these values: amd64, 386 or arm"
+			echo $RTFM_MSG
+			exit 1
+	esac
+fi
+
+if [ -e $GOOS ]
+then
+	echo 'GOOS is empty'
+	echo $RTFM_MSG
+	exit 1
+else
+	case "$GOOS" in
+		linux)
+			;;
+		darwin)
+			;;
+			nacl)
+			;;
+		*)
+			echo "GOOS must be one of these values: linux, darwin or nacl"
+			echo "see http://golang.org/doc/install.html section 'Environment Variables' for details"
+			exit 1
+	esac
+fi
+
 bash clean.bash
 
 rm -f $GOBIN/quietgcc