t/curse: add a Makefile so we can compare speed when using GNU make.

redo: 5.4s
redo -j4: 3.0s
make: 2.3s
make -j4: 1.4s
make SHELL=/bin/dash: 1.2s
make SHELL=/bin/dash -j4: 0.83s

We have some distance to go yet.  Of course, redo is still written in
python, not C, so it's very expensive, and the on-disk dependency store is
very inefficient.

t/curse/check-2.sh

@@ -0,0 +1,12 @@
+COUNT_IN=$(ls *.count | wc -l)
+COUNT_OUT=$(cat *.count | wc -l)
+if [ "$COUNT_IN" != "$COUNT_OUT" ]; then
+	echo "expected $COUNT_IN individual writes, got $COUNT_OUT" >&2
+	exit 42
+fi
+COUNTALL_IN=$(cat in.countall | wc -l)
+COUNTALL_OUT=$(cat out.countall | wc -l)
+if [ "$COUNTALL_IN" != "$COUNTALL_OUT" ]; then
+	echo "expected $COUNTALL_IN allwrites, got $COUNTALL_OUT" >&2
+	exit 43
+fi