Merge topic 'add_subdirectory_system'

2eb30a7036 add_subdirectory: Add SYSTEM option

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !7399

1 files changed, 15 insertions, 9 deletions

diff --git a/Help/prop_tgt/SYSTEM.rst b/Help/prop_tgt/SYSTEM.rst
index 2db6aed..a267738 100644
--- a/Help/prop_tgt/SYSTEM.rst
+++ b/Help/prop_tgt/SYSTEM.rst
@@ -3,14 +3,20 @@ SYSTEM
 
 .. versionadded:: 3.25
 
-Specifies that a target is a ``SYSTEM`` library.  This has the following effects:
+Specifies that a target is a ``SYSTEM`` library.  This has the following
+effects:
 
-* Entries of :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` are treated as ``SYSTEM``
-  include directories when compiling consumers.
-  Entries of :prop_tgt:`INTERFACE_SYSTEM_INCLUDE_DIRECTORIES` are not affected,
-  and will always be treated as ``SYSTEM`` include directories.
+* Entries of :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` are treated as
+  ``SYSTEM`` include directories when compiling consumers.
+  Entries of :prop_tgt:`INTERFACE_SYSTEM_INCLUDE_DIRECTORIES` are not
+  affected, and will always be treated as ``SYSTEM`` include directories.
 
-For imported targets, this property has a default value `ON`, which means that their
-`INTERFACE_INCLUDE_DIRECTORIES` are treated as ``SYSTEM`` by default. If their
-`SYSTEM` property is `OFF`, then their `INTERFACE_INCLUDE_DIRECTORIES` will not be
-treated as ``SYSTEM``, regardless of the value of `IMPORTED_NO_SYSTEM` property.
+For imported targets, this property defaults to true, which means
+that their :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` are treated
+as ``SYSTEM`` by default. If their ``SYSTEM`` property is false,
+then their :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` will not be
+treated as ``SYSTEM``, regardless of the value of the
+:prop_tgt:`IMPORTED_NO_SYSTEM` property.
+
+This target property is initialized from the :prop_dir:`SYSTEM`
+directory property when the target is created.