ref-manual: Added the SDK_PACKAGE_ARCHS variable.

(From yocto-docs rev: 7a0abc52a4b85e98b383a6ac9ed46179a2662f7f)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-variables.xml

@@ -7091,6 +7091,22 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-SDK_PACKAGE_ARCHS'><glossterm>SDK_PACKAGE_ARCHS</glossterm>
+            <glossdef>
+                <para>
+                    Specifies a list of architectures compatible with
+                    the SDK machine.
+                    Separate the entries using spaces and list them in order
+                    of priority.
+                    This variable is set automatically and should not
+                    normally be hand-edited.
+                    The default value for
+                    <filename>SDK_PACKAGE_ARCHS</filename> is "all any noarch
+                    ${SDK_ARCH}-${SDKPKGSUFFIX}""
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-SDKIMAGE_FEATURES'><glossterm>SDKIMAGE_FEATURES</glossterm>
             <glossdef>
                 <para>Equivalent to