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

Added by commit 35d7fe73bba1 ("ccache.bbclass: Make it can be shared
between different builds") in OE-Core.

Fixes [YOCTO #16052]

(From yocto-docs rev: 32818c927bde8014e855b10b1d78d3f09beec024)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
(cherry picked from commit 550ef8340b550f8d4e9c3d0672190dc09592c621)
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index a67090308b..62417d045c 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -1463,6 +1463,12 @@ system and gives an overview of their function and contents.
       :term:`CCACHE_DISABLE` variable can be set to "1" in a recipe to disable
       `Ccache` support. This is useful when the recipe is known to not support it.
 
+   :term:`CCACHE_TOP_DIR`
+      When inheriting the :ref:`ref-classes-ccache` class, the
+      :term:`CCACHE_TOP_DIR` variable can be set to the location of where
+      `Ccache` stores its cache files. This directory can be shared between
+      builds.
+
    :term:`CCLD`
       The minimal command and arguments used to run the linker when the C
       compiler is being used as the linker.