native-compilation: how to force the .eln files to be built

[Ken Brown]

I'm just looking at the feature/native-comp branch for the first time, so I 
apologize in advance if my question has already been asked and answered.

Is there an easy way to force the .eln files to be built if the .elc files are 
up to date?  Here's my use case:

I often have more than one build directory for a given source directory.  The 
different build directories might correspond to different configure options or 
different architectures, for example.  After building in one directory, the .elc 
files in the source directory are all up to date.  If I now build in a different 
directory, the .eln files might be out of date or even non-existent, but they 
don't get (re)built.

Thanks.

Ken