Ninja Multi-Config: Add variable to control aliases in build.ninja

Help/generator/Ninja Multi-Config.rst

@@ -78,4 +78,13 @@ targets built with the generated code.
 As a convenience, ``Ninja Multi-Config`` offers a
 :variable:`CMAKE_NINJA_MULTI_DEFAULT_BUILD_TYPE` setting. If this variable is
 specified, a ``build.ninja`` file will be generated which points to the
-specified ``build-<Config>.ninja`` file.
+specified ``build-<Config>.ninja`` file. In addition, if
+:variable:`CMAKE_NINJA_MULTI_DEFAULT_BUILD_TYPE` is used in conjunction with
+:variable:`CMAKE_NINJA_MULTI_CROSS_CONFIG_ENABLE`, you can also specify
+:variable:`CMAKE_NINJA_MULTI_DEFAULT_BUILD_ALIAS`, which changes the config
+of the ``<target>`` targets in ``build.ninja``. For example, if you set
+:variable:`CMAKE_NINJA_MULTI_DEFAULT_BUILD_TYPE` to ``Release``, but set
+:variable:`CMAKE_NINJA_MULTI_DEFAULT_BUILD_ALIAS` to ``Debug`` or ``all``,
+all ``<target>`` aliases in ``build.ninja`` will resolve to ``<target>:Debug``
+or ``<target>:all``, but custom commands will still use the ``Release``
+configuration.

Help/manual/cmake-variables.7.rst

@@ -425,6 +425,7 @@ Variables that Control the Build
    /variable/CMAKE_MSVCIDE_RUN_PATH
    /variable/CMAKE_MSVC_RUNTIME_LIBRARY
    /variable/CMAKE_NINJA_MULTI_CROSS_CONFIG_ENABLE
+   /variable/CMAKE_NINJA_MULTI_DEFAULT_BUILD_ALIAS
    /variable/CMAKE_NINJA_MULTI_DEFAULT_BUILD_TYPE
    /variable/CMAKE_NINJA_OUTPUT_PATH_PREFIX
    /variable/CMAKE_NO_BUILTIN_CHRPATH

Help/variable/CMAKE_NINJA_MULTI_DEFAULT_BUILD_ALIAS.rst

@@ -0,0 +1,6 @@
+CMAKE_NINJA_MULTI_DEFAULT_BUILD_ALIAS
+-------------------------------------
+
+Controls the config of ``<target>`` aliases in ``build.ninja`` for the
+:generator:`Ninja Multi-Config` generator. See the generator's documentation
+for more details.