patch 8.0.0844: wrong function prototype because of missing static

Problem:    Wrong function prototype because of missing static.
Solution:   Add "static".
diff --git a/src/os_win32.c b/src/os_win32.c
index 4921b50..d3cab02 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -111,6 +111,7 @@
 typedef int HINSTANCE;
 typedef int HWND;
 typedef int INPUT_RECORD;
+typedef int INT;
 typedef int KEY_EVENT_RECORD;
 typedef int LOGFONT;
 typedef int LPBOOL;
@@ -657,13 +658,13 @@
     return NULL;
 }
 
-    int
+    static int
 null_libintl_putenv(const char *envstring UNUSED)
 {
     return 0;
 }
 
-    int
+    static int
 null_libintl_wputenv(const wchar_t *envstring UNUSED)
 {
     return 0;
diff --git a/src/proto/os_win32.pro b/src/proto/os_win32.pro
index 754df4f..4e06298 100644
--- a/src/proto/os_win32.pro
+++ b/src/proto/os_win32.pro
@@ -4,8 +4,6 @@
 void *get_dll_import_func(HINSTANCE hInst, const char *funcname);
 int dyn_libintl_init(void);
 void dyn_libintl_end(void);
-int null_libintl_putenv(const char *envstring);
-int null_libintl_wputenv(const wchar_t *envstring);
 void PlatformId(void);
 void mch_setmouse(int on);
 void mch_update_cursor(void);
diff --git a/src/version.c b/src/version.c
index 2db4ca9..ee0a081 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    844,
+/**/
     843,
 /**/
     842,