FindMFC, CMAKE_MFC_FLAG: Update documentation

FindMFC:
- Synced module documentation with other similar find modules.
- Added examples section.
- Added reference link to CMAKE_MFC_FLAG variable.

CMAKE_MFC_FLAG:
- Added separate examples section.
- Mentioned FindMFC module.
- Used target_compile_definitions() instead of add_definitions().

Help/variable/CMAKE_MFC_FLAG.rst

@@ -8,13 +8,25 @@ It should be set to ``1`` for the static MFC library, and
 ``2`` for the shared MFC library.  This is used in Visual Studio
 project files.
 
+Contents of ``CMAKE_MFC_FLAG`` may use
+:manual:`generator expressions <cmake-generator-expressions(7)>`.
+
+Examples
+^^^^^^^^
+
 Usage example:
 
 .. code-block:: cmake
 
-  add_definitions(-D_AFXDLL)
   set(CMAKE_MFC_FLAG 2)
+
   add_executable(CMakeSetup WIN32 ${SRCS})
 
-Contents of ``CMAKE_MFC_FLAG`` may use
-:manual:`generator expressions <cmake-generator-expressions(7)>`.
+  # Visual Studio generators add this flag automatically based on the
+  # CMAKE_MFC_FLAG value, but generators matching "Make" require it:
+  target_compile_definitions(CMakeSetup PRIVATE _AFXDLL)
+
+See Also
+^^^^^^^^
+
+* The :module:`FindMFC` module to check whether MFC is installed and available.

Modules/FindMFC.cmake

@@ -5,16 +5,45 @@
 FindMFC
 -------
 
-Find Microsoft Foundation Class Library (MFC) on Windows
+Finds the native Microsoft Foundation Class Library (MFC) for developing MFC
+applications on Windows.
 
-Find the native MFC - i.e.  decide if an application can link to the
-MFC libraries.
+.. note::
 
-::
+  MFC is an optional component in Visual Studio and must be installed
+  separately for this module to succeed.
 
-  MFC_FOUND - Was MFC support found
+Once the MFC libraries and headers are found, no additional manual linking is
+needed, as they are part of the development environment.
 
-You don't need to include anything or link anything to use it.
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This module defines the following variables:
+
+``MFC_FOUND``
+  Boolean indicating whether MFC support is found.
+
+Examples
+^^^^^^^^
+
+Using this module to check if the application can link to the MFC libraries:
+
+.. code-block:: cmake
+
+  find_package(MFC)
+
+  if(MFC_FOUND)
+    # Example logic when MFC is available...
+    set(CMAKE_MFC_FLAG 2)
+    add_executable(app WIN32 main.cpp)
+    target_compile_definitions(app PRIVATE _AFXDLL)
+  endif()
+
+See Also
+^^^^^^^^
+
+* The :variable:`CMAKE_MFC_FLAG` variable.
 #]=======================================================================]
 
 # Assume no MFC support