Patch sent upstream:

https://github.com/xbmc/xbmc/pull/7551


From a6d6a1a36ff2dff2586fbad2a068e7df14b55fdc Mon Sep 17 00:00:00 2001
From: Bernd Kuhls <bernd.kuhls@t-online.de>
Date: Sun, 19 Jul 2015 14:12:03 +0200
Subject: [PATCH 1/1] ALSA: fix device change event support

Current uClibc version 0.9.33.2 does not support eventfd_read/write.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
---
 configure.ac                  |    5 ++++-
 xbmc/linux/FDEventMonitor.cpp |   12 ++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index d321f7d..4c6c750 100644
--- a/configure.ac
+++ b/configure.ac
@@ -911,7 +911,7 @@ AC_FUNC_STRFTIME
 AC_FUNC_STRTOD
 AC_FUNC_UTIME_NULL
 AC_FUNC_VPRINTF
-AC_CHECK_FUNCS([atexit dup2 fdatasync floor fs_stat_dev ftime ftruncate getcwd gethostbyaddr gethostbyname gethostname getpagesize getpass gettimeofday inet_ntoa lchown localeconv memchr memmove memset mkdir modf munmap pow rmdir select setenv setlocale socket sqrt strcasecmp strchr strcspn strdup strerror strncasecmp strpbrk strrchr strspn strstr strtol strtoul sysinfo tzset utime posix_fadvise localtime_r])
+AC_CHECK_FUNCS([atexit dup2 fdatasync floor fs_stat_dev ftime ftruncate getcwd gethostbyaddr gethostbyname gethostname getpagesize getpass gettimeofday inet_ntoa lchown localeconv memchr memmove memset mkdir modf munmap pow rmdir select setenv setlocale socket sqrt strcasecmp strchr strcspn strdup strerror strncasecmp strpbrk strrchr strspn strstr strtol strtoul sysinfo tzset utime posix_fadvise localtime_r eventfd_read eventfd_write])
 
 # Check for various sizes
 AC_CHECK_SIZEOF([int])
@@ -2064,6 +2064,9 @@ fi
 if test "$use_alsa" = "yes"; then
   USE_ALSA=1
   AC_DEFINE([USE_ALSA],[1],["Define to 1 if alsa is installed"])
+  if test "$ac_cv_func_eventfd_read" = "yes" -a "$ac_cv_func_eventfd_write" = "yes"; then
+      AC_DEFINE([HAVE_EVENTFD],[1],["Define to 1 if eventfd is installed"])
+  fi
   final_message="$final_message\n  ALSA:\t\tYes"
 else
   USE_ALSA=0
diff --git a/xbmc/linux/FDEventMonitor.cpp b/xbmc/linux/FDEventMonitor.cpp
index 4a41477..84efeb9 100644
--- a/xbmc/linux/FDEventMonitor.cpp
+++ b/xbmc/linux/FDEventMonitor.cpp
@@ -28,6 +28,18 @@
 
 #include "FDEventMonitor.h"
 
+#ifndef HAVE_EVENTFD
+static int eventfd_read(int __fd, eventfd_t *__value)
+{
+  return read(__fd, __value, sizeof(eventfd_t)) == sizeof(eventfd_t) ? 0 : -1;
+}
+
+static int eventfd_write(int __fd, eventfd_t __value)
+{
+  return write(__fd, &__value, sizeof(eventfd_t)) == sizeof(eventfd_t) ? 0 : -1;
+}
+#endif
+
 CFDEventMonitor::CFDEventMonitor() :
   CThread("FDEventMonitor"),
   m_nextID(0),
-- 
1.7.10.4