Conditional Makefile Fragment

[Tom Browder]

In my Makefile.am I would like to do something like this:

if ENABLE_PDF
< 1. lines of normal Make syntax>
else
< 2. lines of normal Make syntax>
endif

When I try it, all the lines appear in the final Makefile, but the
false branch is commented out.

Is there any way to output the true branch and not the false branch?

I think I can use Makefile fragments and include statements but I'd rather not.

Thanks.

-Tom