patch 8.2.5106: default cmdwin mappings are re-mappable

Problem:    Default cmdwin mappings are re-mappable.
Solution:   Make the default mappings not re-mappable. (closes #10580)  Use
            symbols for the first do_map() argument.
diff --git a/src/vim.h b/src/vim.h
index 6362835..1e66d51 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -17,7 +17,7 @@
 # define MSWIN
 #endif
 
-#ifdef MSWIN
+#if defined(MSWIN) && !defined(PROTO)
 # include <io.h>
 #endif
 
@@ -378,7 +378,7 @@
  * We assume that when fseeko() is available then ftello() is too.
  * Note that Windows has different function names.
  */
-#ifdef MSWIN
+#if defined(MSWIN) && !defined(PROTO)
 typedef __int64 off_T;
 # ifdef __MINGW32__
 #  define vim_lseek lseek64
@@ -967,6 +967,11 @@
 #define KEY_OPEN_BACK	0x102
 #define KEY_COMPLETE	0x103	// end of completion
 
+// Used for the first argument of do_map()
+#define MAPTYPE_MAP	0
+#define MAPTYPE_UNMAP	1
+#define MAPTYPE_NOREMAP	2
+
 // Values for "noremap" argument of ins_typebuf().  Also used for
 // map->m_noremap and menu->noremap[].
 #define REMAP_YES	0	// allow remapping