+ "SimGear installation is incomplete or mismatching.")
+endif()
+
+string(STRIP "${SG_VERSION_FILE}" SIMGEAR_DEFINE)
+string(REPLACE "#define SIMGEAR_VERSION " "" SIMGEAR_VERSION "${SIMGEAR_DEFINE}")
+
+if(NOT SIMGEAR_VERSION)
+ message(FATAL_ERROR "Unable to find SimGear or simgear/version.h does not exist/is invalid. "
+ "Make sure you have installed the SimGear ${SimGear_FIND_VERSION} includes. "
+ "When using non-standard locations, please use 'SIMGEAR_DIR' "
+ "to select the SimGear library location to be used.")