[Buildroot] Package overriding

[Arnout Vandecappelle <arnout@mind.be>]

On 18/03/13 03:33, Charles Manning wrote:
[snip]
> For example, I recently needed to add two more configuration lines to
> building bluez_utils.
>
> Instead of:
>
> BLUEZ_UTILS_CONF_OPT = --enable-test --enable-tools
> I wanted
> BLUEZ_UTILS_CONF_OPT = --enable-test --enable-tools --enable-bccmd --enable-dund
>
>
> A logical way I can see to do this would be to have a mechanism
> similar to Package Override but that is applied after the packages are
> parsed.
>
> --- Makefile	(revision 20385)
> +++ Makefile	(working copy)
> @@ -319,11 +319,20 @@
>   -include $(PACKAGE_OVERRIDE_FILE)
>   endif
>
>   include package/*/*.mk
>   include hj/package/*/*.mk
>   include boot/common.mk
>   include linux/linux.mk
>
> +POST_PACKAGE_OVERRIDE_FILE=$(call qstrip,$(BR2_POST_PACKAGE_OVERRIDE_FILE))
> +ifneq ($(POST_PACKAGE_OVERRIDE_FILE),)
> +-include $(POST_PACKAGE_OVERRIDE_FILE)
> +endif
> +
> +
>
> Then have POST_PACKAGE_OVERRIDE_FILE point to a file which has
>
> # Add bluez_utils options we need
> BLUEZ_UTILS_CONF_OPT +=  --enable-bccmd --enable-dund
>
> Does that sound useful?

  The problem with this approach is that it is not reliable. It _happens_ 
to work fine for _CONF_OPT. But it would not work for _DEPENDENCIES, for 
example, because the rule that consumes that variable comes before it. 
And probably there are some variables where it doesn't work at all 
because of some weird double-dollar stuff.

  That's why we just don't want to deal with this kind of changes. The 
override file is meant to be a development tool that allows you to hack 
the source code for a package. For other stuff, you should modify the 
package's .mk file directly.


> Is there a better way?

  In this particular case, the better way is to create new Config.in 
options for bccmd and dund. And send us the patch, of course.


  Regards,
  Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
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