Add separate directory for postinstall intercepts

The scripts/postinst-intercepts will contain all postinstall hooks that
we need to run after all packages have been installed.

If one wants to install such a postinst hook, all it needs to do is put
the hook in this directory and, from the package postinstall scriptlet,
call:
	postinst_intercept <hook_name> <package_name> <var1=...> ...

This will, practically, add the package_name in the list of packages
that need the hook to run and, also, set any variables that would be
needed in the hook. For example, variables like ${libdir}, ${bindir},
etc. that might depend on distribution can be passed on to the script in
this way.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
image.bbclass: add fall-back functionality when running intercepts

If an intercept script fails, it would be helpful to fall-back to
running the postinstall on target's first boot. In order to achieve
that, the postinstalls that install a host intercept hook will have to
return 1, so that the postinstall is marked as unpacked only. If the
intercept hook fails, then we're ok, the postinstalls will be run on
target anyway. If it succeeds, then mark the packages as installed.

This logic was chosen mainly because of rpm backend which saves the
failed postinstalls in /etc/rpm-postinsts. Hence, in order to mark the
packages as installed, all we have to do is delete the scriptlets from
there.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
rootfs_(ipk|deb|rpm).bbclass: check package installation status after ROOTFS_POSTPROCESS_COMMAND

Since the intercept fall-back procedure will change the package
installation status, do the checking after ROOTFS_POSTPROCESS_COMMAND
ends.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gtk-icon-cache.bbclass: use postinst_intercept script

Since the hook has been made a standalone script, use postinst_intercept
script in order to "link" the package to the hook.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
fontcache.bbclass: use the postinst_intercept script

"Link" the package to the postinstall hook by running the
postinst_intercept script.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Add pixbufcache class

All packages exporting pixbuf loaders should inherit this class in order
to generate the correct postinst/postrm scriptlets.

[YOCTO #3852]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gdk-pixbuf: use the new pixbufcache class

[YOCTO #3582]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
librsvg: use the new pixbufcache class

Also, fix the GDK_PIXBUF_QUERYLOADERS path.

[YOCTO #3582]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gnome-keyring: compile schemas on host

gsettings.bbclass offers just that.

[YOCTO #3854]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gtk-immodules-cache: add weak asignment for GTKIMMODULES_PACKAGES

This is needed if the GTKIMMODULES_PACKAGES is changed later, in
do_populate_packages for example. This way, we don't have to add another
dumb asignment in the recipe inheriting this.

[YOCTO #3853]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
gtk+: use gtk-immodules-cache class

In order to have the proper postinst/postrm scriptlets generated for
gtk+ immodules packages, use the already existing class.

[YOCTO #3853]

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>