ntpd: Fix compile with glibc 2.34

This adds a patch from Open embedded to fix compilation with glibc 2.34.
This patch was taken from here:
https://github.com/openembedded/meta-openembedded/blob/master/meta-networking/recipes-support/ntp/ntp/0001-libntp-Do-not-use-PTHREAD_STACK_MIN-on-glibc.patch

It fixes the following build problem:
work_thread.c:45:57: error: missing binary operator before token "("
   45 | #if defined(PTHREAD_STACK_MIN) && THREAD_MINSTACKSIZE < PTHREAD_STACK_MIN
      |                                                         ^~~~~~~~~~~~~~~~~
make[7]: *** [Makefile:892: work_thread.o] Error 1

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

net/ntpd/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ntp
 PKG_VERSION:=4.2.8p15
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/

net/ntpd/patches/0001-libntp-Do-not-use-PTHREAD_STACK_MIN-on-glibc.patch

@@ -0,0 +1,27 @@
+From 082a504cfcc046c3d8adaae1164268bc94e5108a Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Sat, 31 Jul 2021 10:51:41 -0700
+Subject: [PATCH] libntp: Do not use PTHREAD_STACK_MIN on glibc
+
+In glibc 2.34+ PTHREAD_STACK_MIN is not a compile-time constant which
+could mean different stack sizes at runtime on different architectures
+and it also causes compile failure. Default glibc thread stack size
+or 64Kb set by ntp should be good in glibc these days.
+
+Upstream-Status: Pending
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ libntp/work_thread.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/libntp/work_thread.c
++++ b/libntp/work_thread.c
+@@ -41,7 +41,7 @@
+ #ifndef THREAD_MINSTACKSIZE
+ # define THREAD_MINSTACKSIZE	(64U * 1024)
+ #endif
+-#ifndef __sun
++#if !defined(__sun) && !defined(__GLIBC__)
+ #if defined(PTHREAD_STACK_MIN) && THREAD_MINSTACKSIZE < PTHREAD_STACK_MIN
+ # undef THREAD_MINSTACKSIZE
+ # define THREAD_MINSTACKSIZE PTHREAD_STACK_MIN