[gnome-continuous-yocto/gnomeostree-3.28-rocko: 2727/8267] ref-manual: Updated the PACKAGES variable description

[Emmanuele Bassi <ebassi src gnome org>]

commit 826383984d5b4d8ca5c3a7bbcf4bcc0d4a5b55d8
Author: Scott Rifenbark <srifenbark gmail com>
Date:   Wed Sep 21 14:26:06 2016 -0700

    ref-manual: Updated the PACKAGES variable description
    
    Fixes [YOCTO #10294]
    
    Provided text noting that if packages in the PACKAGES list are
    empty are not generated, unless generation is forced through
    the ALLOW_EMPTY variable.
    
    (From yocto-docs rev: 1c89e0edf7e038f733b9b95bb884648d953b9574)
    
    Signed-off-by: Scott Rifenbark <srifenbark gmail com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 documentation/ref-manual/ref-variables.xml |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 8997042..9d53fea 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -9297,6 +9297,18 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
                     for more than one package in <filename>PACKAGES</filename>,
                     it will be assigned to the earliest (leftmost) package.
                 </para>
+
+                <para>
+                    Packages in the variable's list that are empty (i.e. where
+                    none of the patterns in
+                    <filename>FILES_</filename><replaceable>pkg</replaceable>
+                    match any files installed by the
+                    <link linkend='ref-tasks-install'><filename>do_install</filename></link>
+                    task) are not generated, unless generation is forced through
+                    the
+                    <link linkend='var-ALLOW_EMPTY'><filename>ALLOW_EMPTY</filename></link>
+                    variable.
+                </para>
             </glossdef>
         </glossentry>