patch 8.2.3672: build failure with unsigned char

Problem:    Build failure with unsigned char.
Solution:   Use int instead of char.
diff --git a/src/version.c b/src/version.c
index 0686cfa..d1004bb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3672,
+/**/
     3671,
 /**/
     3670,
diff --git a/src/xxd/xxd.c b/src/xxd/xxd.c
index c7b166e..ad0c72f 100644
--- a/src/xxd/xxd.c
+++ b/src/xxd/xxd.c
@@ -253,14 +253,14 @@
 }
 
   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);