extending automake

[Bob Rossi]

Hi,

Up until now, I've just used the canned macros that automake provides.
However, I'm wondering if it has a way that I can extend it.

I basically have an xml file, and a python script, that generates a
header and a source file. I write this in multiple spots in my
Makefile.am

EXTRA_DIST = foo.xml

BUILT_SOURCES = foo.h foo.cc

foo.h foo.cc: $(srcdir)/foo.xml $(top_srcdir)/gen.py
  python $(abs_top_srcdir)/gen.py $(srcdir)/foo.xml

I would like to automake this by writing a wrapper like,
  AM_GEN(foo.xml)

Is this possible? If so, is there some documentation on how to do it?
I looked through the manual and didn't see it, or just missed it.

Thanks,
Bob Rossi