[Omake] Re: Building in subdirectories and variant builds revisited

[David Kågedal]

Aleksey Nogin <anogin at hrl.com> writes:

>> IMO, the impreciseness of the build rules are really orthogonal to the
>> issue of variant builds.
>>
> IMO, the issue of variant builds is orthogonal to out-of-src
> builds. OMake is really good with variant builds - as long as you do
> not mind building one variant at a time. As OMake knows to rebuild
> targets when the command line flags change, you can always switch from
> one variant to another and OMake will know how to rebuild all the
> files that differ between the variants.

There's another kind of "variant build" that hasn't been discussed,
but that I've done many times, and that is building the same thing
with the same options, but for different target architectures.
Typically you'd do this on an NFS-mounted file system and you'd create
different build directories for the different builds, but they would
be run with the same configuration and maybe even the same compiler
command line.

Typical use for an autoconf setup:

 $ tar zxf emacs.tar.gz
 $ mkdir emacs/sparc-solaris
 $ cd emacs/sparc-solaris
 $ ../configure && make

... on another system:

 $ mkdir emacs/x86-linux
 $ cd emacs/x86-linux
 $ ../configure && make

You wouldn't want those two to share the same build directory, and I'm
not even sure that omake would be able to tell when it needs to
recompile.

I don't have any suggestions for improvements in omake right now, but
I will continue to think about it.

-- 
David Kågedal