Autogen: Default AUTOGEN_USE_SYSTEM_INCLUDE to ON if it is not set

Add policy CMP0151 to preserve the old behavior by default.

1 files changed, 28 insertions, 0 deletions

diff --git a/Help/policy/CMP0151.rst b/Help/policy/CMP0151.rst
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+CMP0151
+-------
+
+.. versionadded:: 3.27
+
+AUTOMOC include directory is a system include directory by default.
+
+Headers generated for :ref:`Qt AUTOMOC` are placed in target-specific include
+directories.  CMake 3.26 and older added these as normal include directories.
+CMake 3.27 and newer prefer to add them as system include directories.
+This policy provides compatibility for projects that have not been updated
+to expect this.
+
+If the :prop_tgt:`AUTOGEN_USE_SYSTEM_INCLUDE` target property is set,
+perhaps via the :variable:`CMAKE_AUTOGEN_USE_SYSTEM_INCLUDE` variable,
+then its value is used regardless of the setting of this policy.
+
+The ``OLD`` behavior for this policy is to add autogen include directory to
+the target's include directories.
+The ``NEW`` behavior for this policy is to add autogen include directory to
+the target's system include directories.
+
+This policy was introduced in CMake version 3.27.  Use the
+:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly.
+Unlike many policies, CMake version |release| does *not* warn
+when this policy is not set and simply uses ``OLD`` behavior.
+
+.. include:: DEPRECATED.txt