Issue #6244: Allow detect_tkinter to look for Tcl/Tk 8.6.

Misc/NEWS

@@ -2458,6 +2458,8 @@ Tests
 Build
 -----
 
+- Issue #6244: Allow detect_tkinter to look for Tcl/Tk 8.6.
+
 - Issue #1496032: On alpha, use -mieee when gcc is the compiler.
 
 - Issue #2544: On HP-UX systems, use 'gcc -shared' for linking when

setup.py

@@ -1539,8 +1539,8 @@ class PyBuildExt(build_ext):
         # The versions with dots are used on Unix, and the versions without
         # dots on Windows, for detection by cygwin.
         tcllib = tklib = tcl_includes = tk_includes = None
-        for version in ['8.5', '85', '8.4', '84', '8.3', '83', '8.2',
-                        '82', '8.1', '81', '8.0', '80']:
+        for version in ['8.6', '86', '8.5', '85', '8.4', '84', '8.3', '83',
+                        '8.2', '82', '8.1', '81', '8.0', '80']:
             tklib = self.compiler_obj.find_library_file(lib_dirs,
                                                         'tk' + version)
             tcllib = self.compiler_obj.find_library_file(lib_dirs,