Document 4.0.x build issues on MacOS 10.7
diff --git a/src/source/known-issues.md b/src/source/known-issues.md
index 4fa1bea..46c52c0 100644
@@ -194,3 +194,17 @@
**Fix**: Build Android in an environment that has as few
customizations as possible.
+## Build error with 4.0.x and earlier on MacOS 10.7. ##
+**Symptom**: Building IceCreamSandwich 4.0.x (and older
+versions) fails on MacOS 10.7 with errors similar to this:
+`Undefined symbols for architecture i386: "_SDL_Init"`
+**Cause**: 4.0.x is not compatible with MacOS 10.7.
+**Fix**: Either downgrade to MacOS 10.6, or use the master
+branch, which can be built on MacOS 10.7.
+ $ repo init -b master
+ $ repo sync