diff --git a/configure.ac b/configure.ac
index 197c6222..15ade079 100644
--- a/configure.ac
+++ b/configure.ac
@@ -30,6 +30,7 @@ AC_CONFIG_SRCDIR([Makefile.am])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
+AC_USE_SYSTEM_EXTENSIONS
 
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
 AM_MAINTAINER_MODE
@@ -44,10 +45,10 @@ AC_CHECK_MEMBERS([struct sysinfo.totalram],[],[],[AC_INCLUDES_DEFAULT
 AC_DISABLE_STATIC
 AC_PROG_LIBTOOL
 
-# Require X.Org macros 1.8 or later for MAN_SUBSTS set by XORG_MANPAGE_SECTIONS
+# Require X.Org macros 1.16 or later for XORG_TESTSET_CFLAG
 m4_ifndef([XORG_MACROS_VERSION],
-	  [m4_fatal([must install xorg-macros 1.8 or later before running autoconf/autogen])])
-XORG_MACROS_VERSION(1.8)
+	  [m4_fatal([must install xorg-macros 1.16 or later before running autoconf/autogen])])
+XORG_MACROS_VERSION(1.16)
 XORG_DEFAULT_OPTIONS
 
 PKG_CHECK_MODULES(DRM, [libdrm_intel >= 2.4.23 libdrm])
@@ -87,6 +88,10 @@ if test "x$SHADER_DEBUGGER" = xyes; then
 	fi
 fi
 
+# To build multithread code, gcc uses -pthread, Solaris Studio cc uses -mt
+XORG_TESTSET_CFLAG([THREAD_CFLAGS], [-pthread], [-mt])
+AC_SUBST([THREAD_CFLAGS])
+
 AC_CONFIG_FILES([
 	Makefile
 	benchmarks/Makefile
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 770243ab..4ff4376d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -103,5 +103,5 @@ endif
 endif
 endif
 
-gem_fence_thrash_CFLAGS = $(AM_CFLAGS) -pthread
+gem_fence_thrash_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
 gem_fence_thrash_LDADD = $(LDADD) -lpthread
diff --git a/tests/gem_fence_thrash.c b/tests/gem_fence_thrash.c
index 24147dee..7b679369 100644
--- a/tests/gem_fence_thrash.c
+++ b/tests/gem_fence_thrash.c
@@ -26,7 +26,7 @@
  *
  */
 
-#define _GNU_SOURCE
+#include "config.h"
 
 #include <unistd.h>
 #include <stdlib.h>