package/libkcapi: fix build on riscv32

Fix the following build failure on riscv32:

lib/internal.h:331:20: error: '__NR_io_getevents' undeclared (first use in this function); did you mean 'io_getevents'?
  331 |     return syscall(__NR_io_getevents, ctx, min, max, events, timeout);
      |                    ^~~~~~~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/c828d4330a8888fe8db4299dc2f20759947f329f

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
(cherry picked from commit 5a075b47a86e4e2b147256bd946c9cfd1d3bc15e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libkcapi/0001-Disable-use-of-__NR_io_getevents-when-not-defined.patch

@@ -0,0 +1,42 @@
+From 455c4938f5822c017c7ff79dd2dca638b6410923 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Sun, 15 Nov 2020 18:05:48 -0800
+Subject: [PATCH] Disable use of __NR_io_getevents when not defined
+
+Architectures like riscv32 do not define this syscall, therefore return
+ENOSYS on such architectures
+
+Upstream-Status: Pending
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+Signed-off-by: Stephan Mueller <smueller@chronox.de>
+[Retrieved from:
+https://github.com/smuellerDD/libkcapi/commit/455c4938f5822c017c7ff79dd2dca638b6410923]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ lib/internal.h | 11 +++++++++--
+ 1 file changed, 9 insertions(+), 2 deletions(-)
+
+diff --git a/lib/internal.h b/lib/internal.h
+index 1237827..f765461 100644
+--- a/lib/internal.h
++++ b/lib/internal.h
+@@ -325,10 +325,17 @@ static inline int io_submit(aio_context_t ctx, long n,  struct iocb **iocb)
+     return syscall(__NR_io_submit, ctx, n, iocb);
+ }
+ 
+-static inline int io_getevents(aio_context_t ctx, long min, long max,
+-            struct io_event *events, struct timespec *timeout)
++static inline int io_getevents(__attribute__((unused)) aio_context_t ctx,
++            __attribute__((unused)) long min,
++            __attribute__((unused)) long max,
++            __attribute__((unused)) struct io_event *events,
++            __attribute__((unused)) struct timespec *timeout)
+ {
++#ifdef __NR_io_getevents
+     return syscall(__NR_io_getevents, ctx, min, max, events, timeout);
++#else
++    return -ENOSYS;
++#endif
+ }
+ 
+ /************************************************************