GenEx: Add support for custom transitive compile properties

Teach the `$<TARGET_PROPERTY:...>` generator expression to check for a
new `TRANSITIVE_COMPILE_PROPERTIES` property in the target's link
closure to enable transitive evaluation of named properties through
the link closure, excluding entries guarded by `$<LINK_ONLY:...>`.

Issue: #20416

1 files changed, 17 insertions, 0 deletions

diff --git a/Help/prop_tgt/TRANSITIVE_COMPILE_PROPERTIES.rst b/Help/prop_tgt/TRANSITIVE_COMPILE_PROPERTIES.rst
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index 0000000..a7777c3
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+++ b/Help/prop_tgt/TRANSITIVE_COMPILE_PROPERTIES.rst
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+TRANSITIVE_COMPILE_PROPERTIES
+-----------------------------
+
+.. versionadded:: 3.30
+
+Properties that the :genex:`TARGET_PROPERTY` generator expression, on the
+target and its dependents, evaluates as the union of values collected from
+the transitive closure of link dependencies, excluding entries guarded by
+:genex:`LINK_ONLY`.
+
+The value is a :ref:`semicolon-separated list <CMake Language Lists>`
+of :ref:`custom transitive property <Custom Transitive Properties>` names.
+Any leading ``INTERFACE_`` prefix is ignored, e.g., ``INTERFACE_PROP`` is
+treated as just ``PROP``.
+
+See documentation of the :genex:`TARGET_PROPERTY` generator expression
+for details of custom transitive property evaluation.