package/libgcrypt: fix musl build

Fix the following musl build failure raised since bump to version 1.10.0
in commit d96b9ed0738bae270c479bdaf21eebd4c1f9930d:

In file included from ./jitterentropy.h:98,
                 from ./jitterentropy-base.c:32,
                 from ./rndjent.c:88:
./jitterentropy-base-user.h: In function 'jent_get_cachesize':
./jitterentropy-base-user.h:191:8: warning: implicit declaration of function 'open'; did you mean 'popen'? [-Wimplicit-function-declaration]
  191 |   fd = open(file, O_RDONLY);
      |        ^~~~
      |        popen
./jitterentropy-base-user.h:191:19: error: 'O_RDONLY' undeclared (first use in this function)
  191 |   fd = open(file, O_RDONLY);
      |                   ^~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/f6182fca6a4e2ba29a89f770f17df691d7861f8d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libgcrypt/0002-jitterentropy-Include-fcntl-h-and-limits-h.patch

@@ -0,0 +1,38 @@
+From ffaef0be613121d3ee37867d82932a7a30c2bc6d Mon Sep 17 00:00:00 2001
+From: Heiko Becker <heirecka@exherbo.org>
+Date: Thu, 3 Feb 2022 22:46:41 +0000
+Subject: [PATCH] jitterentropy: Include <fcntl.h> and <limits.h>
+
+* random/jitterentropy-base-user.h: Include <fcntl.h> for O_RDONLY
+* random/jitterentropy-base-user.h: Include <limits.h> for LONG_MAX
+
+--
+
+Fixes the build with musl libc.
+
+Signed-off-by: Heiko Becker <heirecka@exherbo.org>
+
+[Retrieved from:
+https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=ffaef0be613121d3ee37867d82932a7a30c2bc6d]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ random/jitterentropy-base-user.h | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/random/jitterentropy-base-user.h b/random/jitterentropy-base-user.h
+index 326dfbed..389106ff 100644
+--- a/random/jitterentropy-base-user.h
++++ b/random/jitterentropy-base-user.h
+@@ -39,6 +39,9 @@
+  * DAMAGE.
+  */
+ 
++#include <fcntl.h>
++#include <limits.h>
++
+ #ifndef GCRYPT_JITTERENTROPY_BASE_USER_H
+ #define GCRYPT_JITTERENTROPY_BASE_USER_H
+ 
+-- 
+2.11.0
+