patch 8.2.4736: build problem for Cygwin with Motif

Problem:    Build problem for Cygwin with Motif.
Solution:   Undefine ControlMask. (Kelvin Lee, closes #10152)

src/mbyte.c

@@ -84,6 +84,11 @@
 #  define WIN32_LEAN_AND_MEAN
 # endif
 # if defined(FEAT_GUI) || defined(FEAT_XCLIPBOARD)
+#  ifdef __CYGWIN__
+    // ControlMask from <X11/X.h> (included in "vim.h") is conflicting with
+    // <w32api/windows.h> (included in <X11/Xwindows.h>).
+#   undef ControlMask
+#  endif
 #  include <X11/Xwindows.h>
 #  define WINBYTE wBYTE
 # else

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4736,
 /**/
     4735,
 /**/