fix(build): Bundle all assets in source distribution

...even when configured for doing a static binary build with embedded
assets. They don't get installed, but they should be in the dist file in
case the good folks building want to configure it a different way.

Makefile.am

@@ -79,6 +79,10 @@ EXTRA_DIST += $(MANUAL) $(FIGURES)
 EXTRA_DIST += src/embed.rs.in
 EXTRA_DIST += sil.abnf
 
+if EMBEDDED_RESOURCES
+EXTRA_DIST += $(SILEDATA) $(LUALIBRARIES)
+endif
+
 BUILT_SOURCES = $(BUILT_LUA_SOURCES) Makefile-distfiles
 
 CLEANFILES = $(MANUAL)