patch 8.2.1310: configure with Xcode 12 fails to check for tgetent

Problem:    Configure with Xcode 12 fails to check for tgetent.
Solution:   Declare tgetent(). (Ozaki Kiichi, closes #6558)
diff --git a/src/auto/configure b/src/auto/configure
index 9c9a719..41b29c2 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -12106,7 +12106,7 @@
 $as_echo_n "checking for tgetent()... " >&6; }
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-
+int tgetent(char *, const char *);
 int
 main ()
 {
diff --git a/src/configure.ac b/src/configure.ac
index 19ce4c7..598d73c 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -3510,7 +3510,7 @@
 
 if test "x$olibs" = "x$LIBS"; then
   AC_MSG_CHECKING([for tgetent()])
-  AC_TRY_LINK([],
+  AC_TRY_LINK([int tgetent(char *, const char *);],
       [char s[10000]; int res = tgetent(s, "thisterminaldoesnotexist");],
 	AC_MSG_RESULT(yes),
 	AC_MSG_ERROR([NOT FOUND!
diff --git a/src/version.c b/src/version.c
index fb64158..d8dfba8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1310,
+/**/
     1309,
 /**/
     1308,