Just like with the satellite icon we are creating a pixdata structure for
the flag.
The Makefile cleanup in commit df6a9ddd8a21 ("Auto-generate C file
dependencies, and make the build more quiet") removed the rules for
generating the .h file by mistake (I hope).
This adds a more generic rule back in and also makes sure that the data
structures get more useful names.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
