ref-manual: Updated the BBMASK variable description.

(From yocto-docs rev: 0ae8d79993eef08c659e609af7e0afa09dcb9158)

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

documentation/ref-manual/ref-variables.xml

@@ -1200,17 +1200,13 @@
 
         <glossentry id='var-BBMASK'><glossterm>BBMASK</glossterm>
             <info>
-                BBMASK[doc] = "Prevents BitBake from processing specific recipes or recipe append files. Use the BBMASK variable from within conf/local.conf."
+                BBMASK[doc] = "Prevents BitBake from processing specific recipes or recipe append files."
             </info>
             <glossdef>
                 <para role="glossdeffirst">
 <!--                <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> -->
                     Prevents BitBake from processing recipes and recipe
                     append files.
-                    Use the <filename>BBMASK</filename> variable from within the
-                    <filename>conf/local.conf</filename> file found
-                    in the
-                    <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
                 </para>
 
                 <para>
@@ -1218,14 +1214,14 @@
                     to "hide" these <filename>.bb</filename> and
                     <filename>.bbappend</filename> files.
                     BitBake ignores any recipe or recipe append files that
-                    match the expression.
+                    match any of the expressions.
                     It is as if BitBake does not see them at all.
                     Consequently, matching files are not parsed or otherwise
                     used by BitBake.</para>
                 <para>
-                    The value you provide is passed to Python's regular
+                    The values you provide are passed to Python's regular
                     expression compiler.
-                    The expression is compared against the full paths to
+                    The expressions are compared against the full paths to
                     the files.
                     For complete syntax information, see Python's
                     documentation at
@@ -1241,18 +1237,16 @@
      BBMASK = "meta-ti/recipes-misc/"
                     </literallayout>
                     If you want to mask out multiple directories or recipes,
-                    use the vertical bar to separate the regular expression
-                    fragments.
+                    you can specify multiple regular expression fragments.
                     This next example masks out multiple directories and
                     individual recipes:
                     <literallayout class='monospaced'>
-     BBMASK = "meta-ti/recipes-misc/|meta-ti/recipes-ti/packagegroup/"
-     BBMASK .= "|.*meta-oe/recipes-support/"
-     BBMASK .= "|.*openldap"
-     BBMASK .= "|.*opencv"
-     BBMASK .= "|.*lzma"
+     BBMASK += "/meta-ti/recipes-misc/ meta-ti/recipes-ti/packagegroup/"
+     BBMASK += "/meta-oe/recipes-support/"
+     BBMASK += "/meta-foo/.*/openldap"
+     BBMASK += "opencv.*\.bbappend"
+     BBMASK += "lzma"
                     </literallayout>
-                    Notice how the vertical bar is used to append the fragments.
                     <note>
                         When specifying a directory name, use the trailing
                         slash character to ensure you match just that directory