[LV2] Bikeshed: include paths

[David Robillard]

LV2 currently uses header include paths based directly on the URI of the
relevant extension.  This is nice because the same convention can apply
to all LV2 specs (including non-official ones) without any possibility
of clashing.  However:

1) The official LV2 namespace is unfortunately deep and sloppy.

2) Working in a source tree structured this way is unpleasant.

Accordingly, I am thinking of changing the structure used for the
official headers to e.g.

#include <lv2/atom/atom.h>

where "lv2/" is reserved for LV2 itself (as usual with C libraries).

This might be a good time to change so that headers are installed with a
versioned directory to allow for parallel installs,
like /usr/include/lv2-1.0/lv2/... This is the usual best practice for C
libraries, but since LV2 isn't a library I am not sure there is a point.
LV2 isn't allowed to break, so if it did, it would be lv3 anyway?  That
said, *having* to provide an explicit include path avoids some "what am
I building against?" confusion.

Downside: if the source tree is restructured this way, code using the
current/old #include scheme can no longer be built against the LV2
source distribution (without building it first).

Thoughts?

-- 
dr