PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86"
PREFERRED_PROVIDER_virtual/libgl ?= "mesa"
</literallayout>
+ <note>
+ If you set <filename>PREFERRED_PROVIDER</filename>
+ for a <filename>virtual/*</filename> item, then any
+ recipe that
+ <link linkend='var-PROVIDES'><filename>PROVIDES</filename></link>
+ that item that is not selected by
+ <filename>PREFERRED_PROVIDER</filename> is prevented
+ from building, which is usually desirable since this
+ mechanism is designed to select between mutually
+ exclusive alternative providers.
+ </note>
</para>
</glossdef>
</glossentry>