better access to townengine headers from any point in source tree

CMakeLists.txt

@@ -162,7 +162,7 @@ function(link_and_include_deps target)
         # header-only libraries should be marked as "system includes"
         # to suppress compiler warnings in their code (it's not my problem after all)
         target_include_directories(${target}
-                SYSTEM  
+                SYSTEM
                 PRIVATE
                 third-party/physfs/src
                 third-party/physfs/extras
@@ -171,6 +171,9 @@ function(link_and_include_deps target)
                 third-party/stb
         )
 
+        # allow access to headers from any point in source tree
+        target_include_directories(${target} PRIVATE ./)
+
         target_link_libraries(${target} PUBLIC
                                         SDL2::SDL2
                                         SDL2::SDL2main