It's useful to be able to include the makefile without
having introspection enabled.
# Make sure the required variables are set, these should under normal
# circumstances come from introspection.m4
# Make sure the required variables are set, these should under normal
# circumstances come from introspection.m4
-$(if $(INTROSPECTION_GIRS),,$(error Need to define INTROSPECTION_GIRS))
$(if $(INTROSPECTION_SCANNER),,$(error Need to define INTROSPECTION_SCANNER))
$(if $(INTROSPECTION_COMPILER),,$(error Need to define INTROSPECTION_COMPILER))
$(if $(INTROSPECTION_SCANNER),,$(error Need to define INTROSPECTION_SCANNER))
$(if $(INTROSPECTION_COMPILER),,$(error Need to define INTROSPECTION_COMPILER))