VirtualBox module build breakage since commit 39808e451fdf

[Larry Finger]

Hi,

Since commit 39808e451fdf ("kbuild: do not read 
$(KBUILD_EXTMOD)/Module.symvers"), some of the modules for VirtualBox have 
failed to build. There are at least 3 such modules, namely vboxdrv, vboxnetflt, 
and vboxnetadp. The latter 2 require linking to routines exported from the build 
of the first, thus file "Module.symvers" is copied from the build directory of 
vboxdrv into that of the other modules. Even though the documentation says that 
this method should work, and it has in the past, it fails after this commit. The 
necessary external symbols are not found.

Am I missing some step needed to make the copy of "Module.symvers" method work? 
I understand that the method could lead to stale values; however, the build of 
vboxdrv immediately precedes the build of the others, thus the values are always 
current.

Thanks,

Larry