Help: Add documentation and release notes for INSTALL_NAME_DIR genex

Help/manual/cmake-generator-expressions.7.rst

@@ -596,7 +596,8 @@ Target-Dependent Queries
   requirement.
 ``$<INSTALL_PREFIX>``
   Content of the install prefix when the target is exported via
-  :command:`install(EXPORT)` and empty otherwise.
+  :command:`install(EXPORT)`, or when evaluated in
+  :prop_tgt:`INSTALL_NAME_DIR`, and empty otherwise.
 
 Output-Related Expressions
 --------------------------

Help/prop_tgt/INSTALL_NAME_DIR.rst

@@ -10,3 +10,7 @@ installed targets.
 This property is initialized by the value of the variable
 :variable:`CMAKE_INSTALL_NAME_DIR` if it is set when a target is
 created.
+
+This property supports :manual:`generator expressions <cmake-generator-expressions(7)>`.
+In particular, the ``$<INSTALL_PREFIX>`` generator expression can be used to set the
+directory relative to the install-time prefix.

Help/release/dev/install-name-dir-genex.rst

+install-name-dir-genex
+----------------------
+
+* The :prop_tgt:`INSTALL_NAME_DIR` target property now supports
+  :manual:`generator expressions <cmake-generator-expressions(7)>`.
+  In particular, the ``$<INSTALL_PREFIX>`` generator expression can
+  be used to set the directory relative to the install-time prefix.