Build girdir/typelibsdir by using datadir/libdir like in gtk+.
Using INTROSPECTION_GIRDIR/INTROSPECTION_TYPELIBDIR leads to absolute system
paths (make distcheck fails).
$(library_include_HEADERS) \
$(c_sources)
-girdir = $(INTROSPECTION_TYPELIBDIR)
+girdir = $(datadir)/gir-1.0
gir_DATA = Babl-$(BABL_API_VERSION).gir
-typelibsdir = $(INTROSPECTION_TYPELIBDIR)
+typelibsdir = $(libdir)/girepository-1.0
typelibs_DATA = Babl-$(BABL_API_VERSION).typelib
EXTRA_DIST = $(gir_DATA)