+# The following variables have default values which can be overriden
+# A2_BASE the space-separated directories where already built a2 categories can be found
+A2_BASE ?=$(A2_OUTPUT) $(A2_INSTALL_TARGET) $(A2_NATIVE_INSTALL_TARGET) /usr/local/share/a2 /usr/local/lib/a2 /usr/share/a2 /usr/lib/a2
+