File opentrack-fix-build-kalman-filter.patch of Package opentrack

diff -up opentrack/cmake/FindEigen3.cmake.kalman opentrack/cmake/FindEigen3.cmake
--- opentrack/cmake/FindEigen3.cmake.kalman	2018-07-17 23:43:26.000000000 +0200
+++ opentrack/cmake/FindEigen3.cmake	2018-08-03 22:34:01.000000000 +0200
@@ -70,6 +70,7 @@ else (EIGEN3_INCLUDE_DIR)
 
   if(EIGEN3_INCLUDE_DIR)
     _eigen3_check_version()
+    set(EIGEN3_FOUND ${EIGEN3_VERSION_OK})
   endif(EIGEN3_INCLUDE_DIR)
 
   #include(FindPackageHandleStandardArgs)
diff -up opentrack/filter-kalman/CMakeLists.txt.kalman opentrack/filter-kalman/CMakeLists.txt
--- opentrack/filter-kalman/CMakeLists.txt.kalman	2018-06-28 02:24:38.000000000 +0200
+++ opentrack/filter-kalman/CMakeLists.txt	2018-08-03 22:34:49.000000000 +0200
@@ -1,4 +1,4 @@
-find_package(Eigen3 QUIET)
+find_package(Eigen3)
 if(EIGEN3_FOUND)
     otr_module(filter-kalman)
     target_include_directories(opentrack-filter-kalman SYSTEM PUBLIC ${EIGEN3_INCLUDE_DIR})