patch 8.2.3672: build failure with unsigned char

Problem:    Build failure with unsigned char.
Solution:   Use int instead of char.

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3672,
 /**/
     3671,
 /**/

src/xxd/xxd.c

@@ -253,14 +253,14 @@ error_exit(int ret, char *msg)
 }
 
   static void
-exit_on_ferror(char c, FILE *fpi)
+exit_on_ferror(int c, FILE *fpi)
 {
   if (c == EOF && ferror(fpi))
     perror_exit(2);
 }
 
   static void
-putc_or_die(char c, FILE *fpo)
+putc_or_die(int c, FILE *fpo)
 {
   if (putc(c, fpo) == EOF)
     perror_exit(3);