MinGW Makefiles: do not fail if sh.exe is present in the path

The check was added only to fail early in an environment known not to work
at the time:

* https://web.archive.org/web/20120912010035/http://lists.trolltech.com/qt-interest/2006-01/thread00091-0.html

Fixes: #19327

Author: petitlapin

Help/release/dev/mingw_no_sh.rst

@@ -0,0 +1,5 @@
+mingw-no-sh
+-----------
+
+* The :generator:`MinGW Makefiles` generator no longer issues an error if
+  ``sh.exe`` is present in the environment's ``PATH``.

Modules/CMakeMinGWFindMake.cmake

@@ -7,10 +7,5 @@ find_program(CMAKE_MAKE_PROGRAM mingw32-make.exe PATHS
   c:/MinGW/bin /MinGW/bin
   "[HKEY_CURRENT_USER\\Software\\CodeBlocks;Path]/MinGW/bin"
   )
-find_program(CMAKE_SH sh.exe )
-if(CMAKE_SH)
-  message(FATAL_ERROR "sh.exe was found in your PATH, here:\n${CMAKE_SH}\nFor MinGW make to work correctly sh.exe must NOT be in your path.\nRun cmake from a shell that does not have sh.exe in your PATH.\nIf you want to use a UNIX shell, then use MSYS Makefiles.\n")
-  set(CMAKE_MAKE_PROGRAM NOTFOUND)
-endif()
 
-mark_as_advanced(CMAKE_MAKE_PROGRAM CMAKE_SH)
+mark_as_advanced(CMAKE_MAKE_PROGRAM)