multicmake info added (#4250)

* multicmake info added

* wip

* Update reference/tools/cmake/cmake.rst

Co-authored-by: Carlos Zoido <[email protected]>

* Update reference/tools/cmake/cmake.rst

Co-authored-by: Carlos Zoido <[email protected]>

* Update reference/tools/cmake/cmake.rst

Co-authored-by: Carlos Zoido <[email protected]>

* Update reference/tools/cmake/cmake.rst

Co-authored-by: Carlos Zoido <[email protected]>

* Update reference/tools/cmake/cmake.rst

Co-authored-by: Carlos Zoido <[email protected]>

* wip

---------

Co-authored-by: Carlos Zoido <[email protected]>

Author: davidsanfal

reference/tools/cmake/cmake.rst

@@ -35,7 +35,27 @@ when a package is being built directly by Conan (create, install)
             cmake.configure()
             cmake.build()
 
+**Experimental** feature.  ``CMake.configure()``, ``CMake.build()`` and ``CMake.install()`` methods have the **subfolder** parameter in case you have
+more than one ``CMakeLists.txt`` in different folders.
+This feature allows you to call the **configure** **build** and **install** method of each **CMakeLists.txt**
+separately and without mixing the generated files and artifacts, also creating these folders in the
+**build folder** and **package folder**.
 
+In the following example, we can see what it would look like if we had two different **CMakeLists.txt**
+(**cmake_1/CMakeLists.txt** and **cmake_2/CMakeLists.txt**) in the **folder1** and **folder2** folders.
+
+.. code-block:: python
+
+    def build(self):
+        cmake = CMake(self)
+
+        # Configure and build source_folder/cmake_1/CMakeLists.txt in folder1
+        cmake.configure(build_script_folder="cmake_1", subfolder="folder1")
+        cmake.build(subfolder="folder1")
+
+        # Configure and build source_folder/cmake_2/CMakeLists.txt in folder2
+        cmake.configure(build_script_folder="cmake_2" subfolder="folder2")
+        cmake.build(subfolder="folder2")
 
 Reference
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