ref-manual: Added SDKPATH to glossary.

Fixes [YOCTO #5755]

I added this variable to the glossary chapter.

Reported-by: Laszlo Papp <lpapp@kde.org>
(From yocto-docs rev: 0ad0e2ca351ebc52c92404d71502455cf7c042c9)

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

@@ -5866,6 +5866,20 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-SDKPATH'><glossterm>SDKPATH</glossterm>
+            <glossdef>
+                <para>
+                    Defines the path offered to the user for installation
+                    of the SDK that is generated by the OpenEmbedded build
+                    system.
+                    The path appears as the default location for installing
+                    the SDK when you run the SDK's installation script.
+                    You can override the offered path when you run the
+                    script.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-SECTION'><glossterm>SECTION</glossterm>
             <glossdef>
                 <para>The section in which packages should be categorized.