ref-manual/variables.rst: document the REQUIRED_TUNE_FEATURES variable

Very similar to REQUIRED_DISTRO_FEATURES, added by commit a8ef7339ecb9
("features_check.bbclass: Add support for required TUNE_FEATURES") in
OE-Core.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
(From yocto-docs rev: 9652c101092c34233f00418fcc2a84a86fbc9a9b)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index a79d60edcf..5af64a0181 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -7950,6 +7950,15 @@ system and gives an overview of their function and contents.
       the recipe will be skipped, and if the build system attempts to build
       the recipe then an error will be triggered.
 
+   :term:`REQUIRED_TUNE_FEATURES`
+      When inheriting the :ref:`ref-classes-features_check` class, this variable
+      identifies tune features that must exist in the current configuration in
+      order for the :term:`OpenEmbedded Build System` to build the recipe. In
+      other words, if the :term:`REQUIRED_TUNE_FEATURES` variable lists a
+      feature that does not appear in :term:`TUNE_FEATURES` within the current
+      configuration, then the recipe will be skipped, and if the build system
+      attempts to build the recipe then an error will be triggered.
+
    :term:`REQUIRED_VERSION`
       If there are multiple versions of a recipe available, this variable
       determines which version should be given preference.