[Buildroot] [RFC PATCH v4 4/9] libgtk3: remove patch to disable atk-bridge support

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Wed, 20 Jun 2018 11:05:03 -0700, Joseph Kogut wrote:

> > Could we instead keep them optional, by improving this patch ? We
> > really try to keep dependencies to a reasonable level in Buildroot, so
> > it would be nice if we could avoid making those mandatory dependencies
> > of libgtk3.
> >  
> 
> That's a great point, and it's something I hadn't thought of. Would
> you recommend selectively applying the patch to disable the dependency
> on atk-bridge, or some other approach?
> 
> Are there any examples of selectively applying patches that I can use
> as a reference?

We don't want to apply patches conditionally. Instead the patch
*itself* should be smarter, and only use atk if available.

> > > ---- a/configure.ac
> > > -+++ b/configure.ac
> > > -@@ -1349,11 +1349,7 @@
> > > - # Check for Accessibility Toolkit flags
> > > - ########################################
> > > -
> > > --if test x$enable_x11_backend = xyes; then
> > > --   ATK_PACKAGES="atk atk-bridge-2.0"
> > > --else
> > > --   ATK_PACKAGES="atk"
> > > --fi
> > > -+ATK_PACKAGES="atk"
> > > -
> > > - PKG_CHECK_MODULES(ATK, $ATK_PACKAGES)

A rough idea is something like this:

PKG_CHECK_MODULES(ATK, atk)

if test x$enable_x11_backend = xyes; then
	PKG_CHECK_MODULES(ATK_BRIDGE, atk-bridge-2.0,
			  AC_DEFINE([HAVE_ATK_BRIDGE], [1]); ATK_BRIDGE_PACKAGE=atk-bridge-2.0)
fi

In configure.ac, add $ATK_BRIDGE_PACKAGE in:

GTK_PRIVATE_PACKAGES="$ATK_PACKAGES $WAYLAND_PACKAGES $MIR_PACKAGES epoxy >= epoxy_required_version"

And in gtkaccessibility.c, use #ifdef HAVE_ATK_BRIDGE instead of #ifdef
GDK_WINDOWING_X11 to guard the include of <atk-bridge.h> and the call
to atk_bridge_adaptor_init().

Of course, those are rough guidelines, you will probably need to adjust
stuff to actually make it work :-)

Best regards,

Thomas Petazzoni
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com