[OE-core] RFC: magic libtool .la removal

[Burton, Ross]

Hi,

Looking at another recipe that deletes .la files reminded me that
every six months or so I look at this and never actually get anything
done.  Let's try attempt three!

My proposal is that we integrate .la-removal into a core class.
autotools.bbclass should cover 99% of instances as libtool is normally
used in conjunction with auto*.  Have a variable, REMOVE_LIBTOOL_LA,
which controls the behaviour post-install.

"none".  For this recipe, don't remove any .la files.

"libdir".  For this recipe, remove .la files in $base_libdir and
$libdir non-recursively, keeping the .la files in any subdirectories.
This is for packages that use libltdt to load modules, which I believe
needs .la files to work.

"all".  For this recipe, remove all .la files.

I've not written any code yet, but it shouldn't be hard.  Any thoughts?

Ross