mpg123: fix build with alsa

We need to include <time.h> before _POSIX_SOURCE is defined, or the
struct timespec won't be defined for the snd_htimestamp_t typedef.

Closes #4671

srcpkgs/mpg123/patches/fix-alsa_timeval.patch

@@ -0,0 +1,10 @@
+--- src/libout123/modules/alsa.c	2016-06-30 09:04:40.000000000 +0200
++++ src/libout123/modules/alsa.c	2016-08-26 21:45:39.584130976 +0200
+@@ -13,6 +13,7 @@
+      http://mailman.alsa-project.org/pipermail/alsa-devel/2007-June/001684.html
+    ... seems like the conclusion was not carried through.
+  */
++#include <time.h>
+ #define _POSIX_SOURCE
+ #include "out123_int.h"
+ #include <errno.h>

srcpkgs/mpg123/template

@@ -1,7 +1,7 @@
 # Template file for 'mpg123'
 pkgname=mpg123
 version=1.23.6
-revision=1
+revision=2
 build_style=gnu-configure
 configure_args="--with-module-suffix=.so --with-optimization=0
  --with-default-audio=alsa --enable-ipv6=yes --enable-network=yes"