Cached definition of GTEST_* and GMOCK_* variables

This fixes #1091, which introduced a shortcut defining GTEST_FOUND when all targets are defined.
However, those targets are defined by a previous source build of gtest and gmock as well.
Hence, if another catkin package is build below the same top-level project, the corresponding
GTEST_* variables were not defined anymore (because those values were not cached).

g

cmake/test/gtest.cmake

@@ -376,24 +376,24 @@ if(FORCE_GTEST_GMOCK_FROM_SOURCE OR (NOT GMOCK_FOUND AND NOT GTEST_FOUND))
     # set the same variables as find_package()
     # do NOT set in the cache since when using gmock/gtest from source
     # we must always add the subdirectory to have their targets defined
-    set(GMOCK_FOUND ${GMOCK_FROM_SOURCE_FOUND})
-    set(GMOCK_INCLUDE_DIRS ${GMOCK_FROM_SOURCE_INCLUDE_DIRS})
-    set(GMOCK_LIBRARY_DIRS ${GMOCK_FROM_SOURCE_LIBRARY_DIRS})
-    set(GMOCK_LIBRARIES ${GMOCK_FROM_SOURCE_LIBRARIES})
-    set(GMOCK_MAIN_LIBRARIES ${GMOCK_FROM_SOURCE_MAIN_LIBRARIES})
-    set(GMOCK_BOTH_LIBRARIES ${GMOCK_LIBRARIES} ${GMOCK_MAIN_LIBRARIES})
+    set(GMOCK_FOUND ${GMOCK_FROM_SOURCE_FOUND} CACHE INTERNAL "")
+    set(GMOCK_INCLUDE_DIRS ${GMOCK_FROM_SOURCE_INCLUDE_DIRS} CACHE INTERNAL "")
+    set(GMOCK_LIBRARY_DIRS ${GMOCK_FROM_SOURCE_LIBRARY_DIRS} CACHE INTERNAL "")
+    set(GMOCK_LIBRARIES ${GMOCK_FROM_SOURCE_LIBRARIES} CACHE INTERNAL "")
+    set(GMOCK_MAIN_LIBRARIES ${GMOCK_FROM_SOURCE_MAIN_LIBRARIES} CACHE INTERNAL "")
+    set(GMOCK_BOTH_LIBRARIES ${GMOCK_LIBRARIES} ${GMOCK_MAIN_LIBRARIES} CACHE INTERNAL "")
   endif()
 
   if(GTEST_FROM_SOURCE_FOUND)
     # set the same variables as find_package()
     # do NOT set in the cache since when using gtest from source
     # we must always add the subdirectory to have their targets defined
-    set(GTEST_FOUND ${GTEST_FROM_SOURCE_FOUND})
-    set(GTEST_INCLUDE_DIRS ${GTEST_FROM_SOURCE_INCLUDE_DIRS})
-    set(GTEST_LIBRARY_DIRS ${GTEST_FROM_SOURCE_LIBRARY_DIRS})
-    set(GTEST_LIBRARIES ${GTEST_FROM_SOURCE_LIBRARIES})
-    set(GTEST_MAIN_LIBRARIES ${GTEST_FROM_SOURCE_MAIN_LIBRARIES})
-    set(GTEST_BOTH_LIBRARIES ${GTEST_LIBRARIES} ${GTEST_MAIN_LIBRARIES})
+    set(GTEST_FOUND ${GTEST_FROM_SOURCE_FOUND} CACHE INTERNAL "")
+    set(GTEST_INCLUDE_DIRS ${GTEST_FROM_SOURCE_INCLUDE_DIRS} CACHE INTERNAL "")
+    set(GTEST_LIBRARY_DIRS ${GTEST_FROM_SOURCE_LIBRARY_DIRS} CACHE INTERNAL "")
+    set(GTEST_LIBRARIES ${GTEST_FROM_SOURCE_LIBRARIES} CACHE INTERNAL "")
+    set(GTEST_MAIN_LIBRARIES ${GTEST_FROM_SOURCE_MAIN_LIBRARIES} CACHE INTERNAL "")
+    set(GTEST_BOTH_LIBRARIES ${GTEST_LIBRARIES} ${GTEST_MAIN_LIBRARIES} CACHE INTERNAL "")
   endif()
 else()
   if(GMOCK_FOUND)