Exclude example systems from defmain.

quicklisp · quicklisp · commit e10bbfebd40a · 2021-05-13T19:57:10.000-04:00
diff --git a/qlc-meta/excluded-systems.txt b/qlc-meta/excluded-systems.txt
@@ -332,3 +332,5 @@ cl-patterns cl-patterns/incudine
 cl-ana hdf5-cffi
 cl-ana hdf5-cffi.examples
 cl-ana hdf5-cffi.test
+
+defmain example
