Building a subdirectory ignores parent subdir-ccflags (was: Re: [PATCH 1/2] staging: lustre: Add include path to Makefile)

[Joe Perches <joe@perches.com>]

On Mon, 2016-08-15 at 14:14 -0700, Joe Perches wrote:
> On Mon, 2016-08-15 at 23:04 +0200, Greg Kroah-Hartman wrote:
> > On Mon, Aug 15, 2016 at 12:33:23PM -0700, Joe Perches wrote:
> > > Start to rationalize include paths in source code files.
> []
> > > diff --git a/drivers/staging/lustre/Makefile b/drivers/staging/lustre/Makefile
> []
> > > @@ -1,2 +1,5 @@
> > > +subdir-ccflags-y += -I$(srctree)/drivers/staging/lustre/include/
> > > +subdir-ccflags-y += -I$(srctree)/drivers/staging/lustre/lustre/include/
> > > +
> > >  obj-$(CONFIG_LNET)		+= lnet/
> > >  obj-$(CONFIG_LUSTRE_FS)		+= lustre/
> > This is good, but does this break the subdir make command:
> > 	make M=drivers/staging/lustre/foo_dir/
> > ?
> hmm, yeah, it does.  Oh well, nevermind for awhile.
> > I remember the last time I tried to clean this up, it took a while...
> It seems like something the build tools should
> handle correctly now, but I'll look at it.

Perhaps making a specific directory should also walk up
any parent directory Makefiles looking for subdir flags.

Is that unreasonable?  Any suggestions?