package/rng-tools: fix musl build

Fix the following musl build failure raised since bump to version 6.14
in commit 5292d1cf9a:

/home/buildroot/autobuild/instance-0/output-1/host/opt/ext-toolchain/bin/../lib/gcc/i586-buildroot-linux-musl/9.3.0/../../../../i586-buildroot-linux-musl/bin/ld: rngd-rngd_jitter.o: in function `rngd_notime_start':
rngd_jitter.c:(.text+0xdc2): undefined reference to `pthread_attr_setaffinity_np'

Fixes:
 - http://autobuild.buildroot.org/results/3ec7df86856aa9bee2f18a8faa44fd58bc8a6657

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/rng-tools/0001-Adding-ability-to-detect-non-posix-extensions-for-pthreads.patch

@@ -0,0 +1,43 @@
+From d1840e54a15fc454936cada10cce7fd91d06232b Mon Sep 17 00:00:00 2001
+From: Neil Horman <nhorman@gmail.com>
+Date: Thu, 15 Jul 2021 08:43:01 -0400
+Subject: [PATCH] Adding ability to detect non-posix extensions for pthreads
+
+Theres a desire to build rngd with musl, which doesn't have all the gnu
+extensions (but it has some).  So test for those.  Note, this requires
+the addition of the USE_EXTENSIONS macro to enable -d_GNU_SOURCE
+
+Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
+
+[Retrieved from:
+https://github.com/nhorman/rng-tools/commit/d1840e54a15fc454936cada10cce7fd91d06232b]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ configure.ac | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index 0fe06fc..de7dca3 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -25,6 +25,7 @@ AC_CANONICAL_TARGET dnl required for broken AX_PTHREAD
+ AM_INIT_AUTOMAKE([foreign])
+ AC_CONFIG_HEADERS([rng-tools-config.h])
+ AC_CONFIG_MACRO_DIRS([m4])
++AC_USE_SYSTEM_EXTENSIONS
+ 
+ dnl Parse options
+ 
+@@ -100,6 +101,12 @@ AS_IF(
+ 	], [AC_MSG_NOTICE([Disabling JITTER entropy source])]
+ )
+ 
++AC_CHECK_DECL(pthread_attr_setaffinity_np,
++		[AC_DEFINE([HAVE_PTHREAD_ATTR_SETAFFINITY], 1,[Set ATTR_SETAFFINITY])],
++		[ AC_CHECK_DECL(pthread_setaffinity_np,
++		   [AC_DEFINE([HAVE_PTHREAD_SETAFFINITY],1, [Set PTHREAD_SETAFFINITY])], [ AC_MSG_ERROR([Neither pthread_setaffinity_np nor pthread_attr_setaffinity_np found])],[[#include <pthread.h>]])
++		], [[#include <pthread.h>]])
++
+ AS_IF(
+ 	[ test "x$with_nistbeacon" != "xno"],
+ 	[

package/rng-tools/0002-Allow-for-use-of-either-pthread-affinity-set-methods.patch

@@ -0,0 +1,49 @@
+From 5caa086dc14cecf68d1a5c31e87ba1efb2c00893 Mon Sep 17 00:00:00 2001
+From: Neil Horman <nhorman@gmail.com>
+Date: Thu, 15 Jul 2021 08:48:10 -0400
+Subject: [PATCH] Allow for use of either pthread affinity set methods
+
+musl has support for pthread_setaffinity_np, but not
+pthread_attr_setaffinity_np.  so check for hte existence of either
+function in configure, and use the appropriate one.
+
+Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
+
+[Retrieved from:
+https://github.com/nhorman/rng-tools/commit/5caa086dc14cecf68d1a5c31e87ba1efb2c00893]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ rngd_jitter.c | 15 ++++++++++++++-
+ 1 file changed, 14 insertions(+), 1 deletion(-)
+
+diff --git a/rngd_jitter.c b/rngd_jitter.c
+index ea29436..5c7e09e 100644
+--- a/rngd_jitter.c
++++ b/rngd_jitter.c
+@@ -67,12 +67,25 @@ static int rngd_notime_start(void *ctx,
+ 	for(i=i-1;i>=0;i--) {
+ 		CPU_SET(i,cpus);
+ 	}
+-	pthread_attr_setaffinity_np(&thread_ctx->notime_pthread_attr, cpusize, cpus);
+ 
++        /*
++	 * Note that only one of:
++	 * HAVE_PTHREAD_ATTR_SETAFFINITY
++	 * and
++	 * HAVE_PTHREAD_SETAFFINITY
++	 * Will ever be set, as per the configure.ac logic
++	 */
++#ifdef HAVE_PTHREAD_ATTR_SETAFFINITY
++	pthread_attr_setaffinity_np(&thread_ctx->notime_pthread_attr, cpusize, cpus);
++#endif
+ 	ret = -pthread_create(&thread_ctx->notime_thread_id,
+ 				&thread_ctx->notime_pthread_attr,
+ 				start_routine, arg);
+ 
++#ifdef HAVE_PTHREAD_SETAFFINITY
++	pthread_setaffinity_np(&thread_ctx->notime_thread_id, cpusize, cpus);
++#endif
++
+ 	CPU_FREE(cpus);
+ 	return ret;
+ }