user-manual-metadata.xml: Add details about environment variables used by BitBake

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/doc/user-manual/user-manual-metadata.xml b/doc/user-manual/user-manual-metadata.xml
index 621b376d375cbf6206593318ac0bce1cd0356c08..a67d6b1b1aef8df3578b6bedc281525aca695c3b 100644 (file)
--- a/doc/user-manual/user-manual-metadata.xml
+++ b/doc/user-manual/user-manual-metadata.xml
@@ -957,6 +957,19 @@
         <section id='parsing-configuration-files'>
             <title>Configuration files</title>
 
+            <para>
+                Prior to parsing configuration files, Bitbake looks
+                at certain variables, including:
+                <itemizedlist>
+                    <listitem><para><filename>BB-ENV-WHITELIST</filename></para></listitem>
+                    <listitem><para><filename>BB_PRESERVE-ENV</filename></para></listitem>
+                    <listitem><para><filename>BB_ENV_EXTRAWHITE</filename></para></listitem>
+                    <listitem><para><filename>BB_ORIG_ENV</filename></para></listitem>
+                    <listitem><para><filename>PREFERRED_VERSIONS</filename></para></listitem>
+                    <listitem><para><filename>PREFERRED_PROVIDERS</filename></para></listitem>
+                </itemizedlist>
+            </para>
+
             <para>
                 The first kind of metadata in BitBake is configuration metadata.
                 This metadata is global, and therefore affects all packages and