[PATCH] dtc: Add -i option to support search paths

[Jon Loeliger]

> It is often inconvenient to place device tree files in the same directory
> as their includes, or to specify the full path to include files.
> 
> An example of this is in U-Boot where we have a .dtsi file for each SOC
> type, and this is included by the board .dts file. We need to either use
> a mechanism like:
> 
> /include/ ARCH_CPU_DTS
> 
> with sed or cpp to perform the replacement with the correct path, or
> we must specify the full path in the file:
> 
> /include/ "../../arch/arm/dts/tegra20.dtsi"
> 
> The first option is not desirable since it requires anyone compiling the
> file to first pre-process it. The second is not desirable since it
> introduces a path which is project-specific into a file which is supposed
> to be a hardware description. For example Linux and U-Boot are unlikely to
> put these include files in the same place.
> 
> It is much more convenient to specify the search patch on the command line
> as is done with C pre-processors, for example.
> 
> Introduce a -i option to add to the list of search paths used to find
> source and include files.
> 
> We cannot use -I as it is already in use. Other suggestions welcome.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>

Any comments here?  I'm inclined to aply it as is.

Thanks,
jdl