Resolve "Refactoring WOLF installation system"

Closes #451 (closed)

test/gtest/CMakeLists.txt

@@ -72,7 +72,7 @@ function(wolf_add_gtest target)
   if(${CMAKE_VERSION} VERSION_LESS "3.11.0") 
     add_dependencies(${target} libgtest)
     target_link_libraries(${target} libgtest)
-    target_include_directories(${target} ${GTEST_INCLUDE_DIRS})
+    target_include_directories(${target} PUBLIC ${GTEST_INCLUDE_DIRS})
   else()
     target_link_libraries(${target} PUBLIC gtest_main)
   endif()