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.
diff --git a/src/map.c b/src/map.c
index 9570285..2850a3f 100644
--- a/src/map.c
+++ b/src/map.c
@@ -1273,7 +1273,7 @@
     int		i;
     int		fuzzy;
     int		match;
-    int		score;
+    int		score = 0;
     fuzmatch_str_T  *fuzmatch;
 
     fuzzy = cmdline_fuzzy_complete(pat);
diff --git a/src/os_win32.c b/src/os_win32.c
index da48bfd..1adaaed 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -8378,7 +8378,7 @@
  * 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;
diff --git a/src/proto/os_win32.pro b/src/proto/os_win32.pro
index 706cbd6..dd2c27e 100644
--- a/src/proto/os_win32.pro
+++ b/src/proto/os_win32.pro
@@ -85,5 +85,5 @@
 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 : */
diff --git a/src/version.c b/src/version.c
index 66dba17..82ac4ea 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5125,
+/**/
     5124,
 /**/
     5123,