Milter-greylist

>  > By the way, the use of "sync" should be removed, too, it
>  > doesn't make any sense.
> 
> It forces a sort of barrier that build-programs with dirty buffers
> (or the kernel's write-cache) should now flush and finalize the
> built files on-disk. De-facto this improved reliability of builds
> for me over NFS, whatever the "science" behind the curtains
> 

If the sync helps you isn't it possible to rather include into your
calling script/program/Makefile like in that sequence:

configure <parameters>
make <whatever parameters like: -j n >
sync

Than the use of sync becomes your own magic.