Catch an attempt to "make" without "shell-setup".

diff --git a/Makefile b/Makefile
index 28e2824..a139c25 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,11 @@
 NAME:=measurements
 empty:=
+
 # $(OO) is now taken from shell-setup.
+ifeq ($(OO),)
+$(error You must source "shell-setup" in the shell before running make.)
+endif
+
 
 IDL_TYPES:=net/mattmccutchen/measurements/XMeasurementsAddIn