-include_directories(${PROJECT_SOURCE_DIR})
-include_directories(${PROJECT_SOURCE_DIR}/simgear/canvas/ShivaVG/include)
-include_directories(${PROJECT_BINARY_DIR}/simgear)
+# use BEFORE to ensure local directories are used first,
+# ahead of system-installed libs
+include_directories(BEFORE ${PROJECT_SOURCE_DIR})
+include_directories(BEFORE ${PROJECT_SOURCE_DIR}/simgear/canvas/ShivaVG/include)
+include_directories(BEFORE ${PROJECT_BINARY_DIR}/simgear)