Portfile configuration parameter to replace other ports

[Francisco Garcia]

I have just created my first two port contributions. I submitted one
but I am having problems to decide the best approach for the second
one.

I modified the ctags portfile to build the latest svn/trunk version
instead of using the official release. The portfile is here:

https://github.com/fgarcia/macports/blob/master/devel/ctags-devel/Portfile

Since the official release lacks support for ObjectiveC I came up with
two solutions:

1. Create a new port named "ctags-devel". That will show it is not an
official release

2. Build a patch file for the ctags Portfile

I am not sure which one is the normal way to deal with such
situations. I went for point (1) but that port will collide with the
ctags port. I know about the parameter to make ctags-devel to conflict
with ctags, but I cannot find one where I can say that ctags-devel
"provides" plain ctags too. For example, MacVim depends on ctags and I
would like an easy way to avoid this dependency conflict.

thanks
Francisco