https://bugs.gentoo.org/show_bug.cgi?id=423305
https://bitbucket.org/BattleClinic/gtkevemon/changeset/4c365033418e

# HG changeset patch
# User ChickenMan <chickenman@exhale.de>
# Date 1341445681 -7200
# Node ID 4c365033418e2213caff57a0917851cc18c7f1a1
# Parent  0b8a490b5f491bdd4a36d85918479595c861d3db
Fix compilation on systems using pthreads and gcc 4.7.x

This fixes issue 1.
Thanks to l0ser140 for reporting and initial patch.

--- src/thread.h
+++ src/thread.h
@@ -13,7 +13,15 @@
 #ifndef THREAD_HEADER
 #define THREAD_HEADER
 
-#if defined(_POSIX_THREADS) || defined(__SunOS)
+#if defined(__linux__) \
+    || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) \
+    || defined(__DragonFly__) \
+    || defined(__APPLE__) \
+    || defined(__SunOS)
+#  include <unistd.h> // for _POSIX_THREADS
+#endif
+
+#if defined(_POSIX_THREADS)
 #  include "thread_posix.h"
 #elif defined(WIN32)
 #  include "thread_win32.h"