ref-manual: Added GCCVERSION variable description to glossary.

(From yocto-docs rev: f48ffe39e2d0c1bc57579e4ee457c72b7c626ad1)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-variables.xml

@@ -5228,6 +5228,28 @@
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-GCCVERSION'><glossterm>GCCVERSION</glossterm>
+            <info>
+                GCCVERSION[doc] = "Specifies the default version of the GNU C Compiler (GCC) to use."
+            </info>
+            <glossdef>
+                <para role="glossdeffirst">
+<!--                <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> -->
+                    Specifies the default version of the GNU C Compiler (GCC)
+                    used for compilation.
+                    By default, <filename>GCCVERSION</filename> is set to
+                    "8.x" in the
+                    <filename>meta/conf/distro/include/tcmode-default.inc</filename>
+                    include file:
+                    <literallayout class='monospaced'>
+     GCCVERSION ?= "8.%"
+                    </literallayout>
+                    You can override this value by setting it in a configuration
+                    file such as the <filename>local.conf</filename>.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-GDB'><glossterm>GDB</glossterm>
             <info>
                 GDB[doc] = "The minimal command and arguments to run the GNU Debugger."