Squashed 'third_party/eigen/' content from commit 61d72f6

Change-Id: Iccc90fa0b55ab44037f018046d2fcffd90d9d025
git-subtree-dir: third_party/eigen
git-subtree-split: 61d72f6383cfa842868c53e30e087b0258177257
diff --git a/demos/CMakeLists.txt b/demos/CMakeLists.txt
new file mode 100644
index 0000000..b0d2edd
--- /dev/null
+++ b/demos/CMakeLists.txt
@@ -0,0 +1,13 @@
+project(EigenDemos)
+
+add_custom_target(demos)
+
+if(NOT EIGEN_TEST_NOQT)
+  find_package(Qt4)
+  if(QT4_FOUND)
+    add_subdirectory(mandelbrot)
+    add_subdirectory(opengl)
+  else(QT4_FOUND)
+    message(STATUS "Qt4 not found, so disabling the mandelbrot and opengl demos")
+  endif(QT4_FOUND)
+endif()