Cause all cmake builds to fail

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 479487f..5b2e0d7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,3 +1,4 @@
+barf
 #
 # CMake build system design considerations:
 #