slight restructure of CMakeLists

CMakeLists.txt

@@ -187,7 +187,9 @@ function(link_and_include_deps target)
 endfunction()
 
 
-function(use_townengine target)
+function(use_townengine target sources)
+        add_executable(${target} ${sources})
+
         # system libraries
         find_library(MATH_LIBRARY m)
         if(MATH_LIBRARY)
@@ -219,7 +221,9 @@ endfunction()
 give_options(${TOWNENGINE_TARGET})
 link_and_include_deps(${TOWNENGINE_TARGET})
 
-add_subdirectory(apps/testgame)
+if (${CMAKE_PROJECT_NAME} MATCHES townengine)
+        add_subdirectory(apps/testgame)
+endif ()
 
 # zip up assets
 # currently, you must run cmake from the project root dir for this to work correctly