mlt: add universal variant

[ryandesign (Ryan Carsten Schmidt)]

A universal variant should be added to the mlt port. The reason given in the port for why it is disabled is:

# frei0r-plugins is not universal
universal_variant   no

This is no longer correct; frei0r-plugins does have a universal variant now.

Just removing these lines is not enough because mlt is not currently using -arch flags, which it should be doing anyway, even for non-universal builds.

Just adding -arch flags to CFLAGS and LDFLAGS isn't enough either, because then the universal build fails, saying:

cannot use 'dependencies' output with multiple -arch options

To work around that we may need to use the muniversal portgroup.

[ddennedy (Dan Dennedy)]

Sorry, but I am not volunteering to fix this. There was a patch submitted to the mailing list, but it interfered with builds for other platforms. It looks there is still a lot of changes needed in the build system to accommodate it.

[ddennedy (Dan Dennedy)]

Here is a link to the mailing list thread and patch if someone wants to finish the work: ​https://www.mail-archive.com/mlt-devel@lists.sourceforge.net/msg04058.html

Alternatively, it could be a patch for the MacPorts mlt Port instead of merged upstream.

[ryandesign (Ryan Carsten Schmidt)]

Ah! Thanks for the pointer to the existing mailing list discussion. I agree with the analysis that the cause of the error is using CFLAGS where CPPFLAGS should have been used, but I see fixing it is more involved.

I'm trying to instead work around the problem by using the muniversal portgroup. I'm running into some problems but they're related to the portgroup, not mlt. Hopefully I can figure out that problem soon and get it working; I'll attach a diff here for your approval when I do.

I'd really like to get a universal variant for mlt, because the synfig port, which I maintain, will depend on mlt in the next version, and I want synfig to continue to have a universal variant then.

[ryandesign (Ryan Carsten Schmidt)]

r141539