From c3e845ab7efeca743cb1fb6dbba7f74b474c5ecc Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Sun, 1 Mar 2015 16:35:29 -0800
Subject: [PATCH] Only enable doc target if breathe is available

---
 doc/CMakeLists.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 0dda20fe..61b817d4 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -1,3 +1,8 @@
+if (NOT EXISTS ${FORMAT_SOURCE_DIR}/breathe/breathe)
+  message(STATUS "Target 'doc' disabled (requires breathe module)")
+  return ()
+endif ()
+
 foreach (program doxygen sphinx-build)
   find_program(${program} ${program})
   if (NOT ${program})