Help: Document the CMAKE_MSVCIDE_RUN_PATH variable.

Help/manual/cmake-variables.7.rst

@@ -319,6 +319,7 @@ Variables that Control the Build
    /variable/CMAKE_MODULE_LINKER_FLAGS_CONFIG
    /variable/CMAKE_MODULE_LINKER_FLAGS_CONFIG_INIT
    /variable/CMAKE_MODULE_LINKER_FLAGS_INIT
+   /variable/CMAKE_MSVCIDE_RUN_PATH
    /variable/CMAKE_NINJA_OUTPUT_PATH_PREFIX
    /variable/CMAKE_NO_BUILTIN_CHRPATH
    /variable/CMAKE_NO_SYSTEM_FROM_IMPORTED

Help/variable/CMAKE_MSVCIDE_RUN_PATH.rst

@@ -0,0 +1,10 @@
+CMAKE_MSVCIDE_RUN_PATH
+----------------------
+
+Extra PATH locations that should be used when executing
+:command:`add_custom_command` or :command:`add_custom_target` when using the
+:generator:`Visual Studio 9 2008` (or above) generator. This allows
+for running commands and using dll's that the IDE environment is not aware of.
+
+If not set explicitly the value is initialized by the ``CMAKE_MSVCIDE_RUN_PATH``
+environment variable, if set, and otherwise left empty.