ncurses: Fix configure tests for exit and mbstate_t

These tests do not include needed headers which results in warnings and
as errors when using -Werror or latest clang e.g.

(From OE-Core rev: 92f191c304b5d53c14be23f7a5d57b0f9f101767)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/ncurses/files/exit_prototype.patch

@@ -0,0 +1,22 @@
+Add needed headers for including mbstate_t and exit()
+
+Upstream-Status: Inappropriate [Reconfigure will solve it]
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+--- a/configure
++++ b/configure
+@@ -3422,6 +3422,7 @@ rm -f "conftest.$ac_objext" "conftest.$a
+   cat >"conftest.$ac_ext" <<_ACEOF
+ #line 3423 "configure"
+ #include "confdefs.h"
++#include <stdlib.h>
+ $ac_declaration
+ int
+ main (void)
+@@ -12997,6 +12998,7 @@ cat >"conftest.$ac_ext" <<_ACEOF
+ #include <stdlib.h>
+ #include <stdarg.h>
+ #include <stdio.h>
++#include <wchar.h>
+ #ifdef HAVE_LIBUTF8_H
+ #include <libutf8.h>
+ #endif

meta/recipes-core/ncurses/ncurses_6.3+20220423.bb

@@ -3,6 +3,7 @@ require ncurses.inc
 SRC_URI += "file://0001-tic-hang.patch \
            file://0002-configure-reproducible.patch \
            file://0003-gen-pkgconfig.in-Do-not-include-LDFLAGS-in-generated.patch \
+           file://exit_prototype.patch \
            "
 # commit id corresponds to the revision in package version
 SRCREV = "20db1fb41ec91cd8a1f528e770362092c5403378"