patch 8.2.5125: MS-Windows: warnings from MinGW compiler

Problem:    MS-Windows: warnings from MinGW compyler.
Solution:   Use "volatile". (Yasuhiro Matsumoto, closes #10589)  Initialize
            variable.

src/map.c

@@ -1273,7 +1273,7 @@ ExpandMappings(
     int		i;
     int		fuzzy;
     int		match;
-    int		score;
+    int		score = 0;
     fuzmatch_str_T  *fuzmatch;
 
     fuzzy = cmdline_fuzzy_complete(pat);

src/os_win32.c

@@ -8378,7 +8378,7 @@ stop_timeout(void)
  * This function is not expected to fail, but if it does it still returns a
  * valid flag pointer; the flag will remain stuck at zero.
  */
-    const int *
+    volatile int *
 start_timeout(long msec)
 {
     BOOL ret;

src/proto/os_win32.pro

@@ -85,5 +85,5 @@ int get_conpty_fix_type(void);
 void resize_console_buf(void);
 char *GetWin32Error(void);
 void stop_timeout(void);
-const int *start_timeout(long msec);
+volatile int *start_timeout(long msec);
 /* vim: set ft=c : */

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5125,
 /**/
     5124,
 /**/