diff --git a/desmume/src/frontend/posix/cli/Makefile.am b/desmume/src/frontend/posix/cli/Makefile.am
index 4fde1bc5c..fdfc13ec4 100644
--- a/desmume/src/frontend/posix/cli/Makefile.am
+++ b/desmume/src/frontend/posix/cli/Makefile.am
@@ -5,4 +5,4 @@ AM_CPPFLAGS += $(SDL_CFLAGS) $(ALSA_CFLAGS) $(LIBAGG_CFLAGS) $(GLIB_CFLAGS) $(GT
 
 bin_PROGRAMS = desmume-cli
 desmume_cli_SOURCES = main.cpp ../shared/sndsdl.cpp ../shared/ctrlssdl.h ../shared/ctrlssdl.cpp
-desmume_cli_LDADD = ../libdesmume.a $(SDL_LIBS) $(ALSA_LIBS) $(LIBAGG_LIBS) $(GLIB_LIBS) $(GTHREAD_LIBS) $(LIBSOUNDTOUCH_LIBS)
+desmume_cli_LDADD = ../libdesmume.a $(X_LIBS) -lX11 $(SDL_LIBS) $(ALSA_LIBS) $(LIBAGG_LIBS) $(GLIB_LIBS) $(GTHREAD_LIBS) $(LIBSOUNDTOUCH_LIBS)
diff --git a/desmume/src/frontend/posix/cli/main.cpp b/desmume/src/frontend/posix/cli/main.cpp
index 9158fb7f6..fee0b4253 100644
--- a/desmume/src/frontend/posix/cli/main.cpp
+++ b/desmume/src/frontend/posix/cli/main.cpp
@@ -18,6 +18,7 @@
  * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
+#include <X11/Xlib.h>
 #include <SDL.h>
 #include <SDL_thread.h>
 #include <stdlib.h>
@@ -641,6 +642,12 @@ int main(int argc, char ** argv) {
 
   execute = true;
 
+  /* X11 multi-threading support */
+  if(!XInitThreads())
+    {
+      fprintf(stderr, "Warning: X11 not thread-safe\n");
+    }
+
   if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) == -1)
     {
       fprintf(stderr, "Error trying to initialize SDL: %s\n",
diff --git a/desmume/src/frontend/posix/configure.ac b/desmume/src/frontend/posix/configure.ac
index e300e31b1..c87a152a1 100644
--- a/desmume/src/frontend/posix/configure.ac
+++ b/desmume/src/frontend/posix/configure.ac
@@ -53,6 +53,9 @@ AC_CHECK_LIB(zzip, zzip_open, [
 		AC_MSG_RESULT(no))
 ])
 
+dnl - Check for X11
+AC_PATH_X
+
 dnl - Check for SDL
 AC_PATH_PROGS(SDLCONFIG, [sdl-config sdl11-config])
 if test ! "x$SDLCONFIG" = "x" ; then
diff --git a/desmume/src/frontend/posix/gtk-glade/Makefile.am b/desmume/src/frontend/posix/gtk-glade/Makefile.am
index 936f9298e..2db0f2494 100644
--- a/desmume/src/frontend/posix/gtk-glade/Makefile.am
+++ b/desmume/src/frontend/posix/gtk-glade/Makefile.am
@@ -31,6 +31,7 @@ desmume_glade_SOURCES =  \
 	../../../driver.h ../../../driver.cpp
 
 desmume_glade_LDADD = ../libdesmume.a \
+			$(X_LIBS) -lX11 \
 			$(SDL_LIBS) $(GTKGLEXT_LIBS) $(LIBGLADE_LIBS) \
 			$(GTHREAD_LIBS) $(ALSA_LIBS) $(LIBAGG_LIBS) \
 			$(LIBSOUNDTOUCH_LIBS)
diff --git a/desmume/src/frontend/posix/gtk-glade/main.cpp b/desmume/src/frontend/posix/gtk-glade/main.cpp
index 72f852455..11469aaaa 100755
--- a/desmume/src/frontend/posix/gtk-glade/main.cpp
+++ b/desmume/src/frontend/posix/gtk-glade/main.cpp
@@ -533,6 +533,12 @@ int main(int argc, char *argv[]) {
 
   init_configured_features( &my_config);
 
+  /* X11 multi-threading support */
+  if(!XInitThreads())
+    {
+      fprintf(stderr, "Warning: X11 not thread-safe\n");
+    }
+
   if (!g_thread_supported())
     g_thread_init( NULL);
 
diff --git a/desmume/src/frontend/posix/gtk/Makefile.am b/desmume/src/frontend/posix/gtk/Makefile.am
index 83d94fc7e..76a206c15 100644
--- a/desmume/src/frontend/posix/gtk/Makefile.am
+++ b/desmume/src/frontend/posix/gtk/Makefile.am
@@ -25,7 +25,7 @@ desmume_SOURCES = \
 	cheatsGTK.h cheatsGTK.cpp \
 	main.cpp main.h
 desmume_LDADD = ../libdesmume.a \
-	$(SDL_LIBS) $(GTK_LIBS) $(GTHREAD_LIBS) $(ALSA_LIBS) $(LIBAGG_LIBS) $(LIBSOUNDTOUCH_LIBS)
+	$(X_LIBS) -lX11 $(SDL_LIBS) $(GTK_LIBS) $(GTHREAD_LIBS) $(ALSA_LIBS) $(LIBAGG_LIBS) $(LIBSOUNDTOUCH_LIBS)
 if HAVE_LIBOSMESA
 desmume_LDADD += $(OSMESA_LIBS)
 else
diff --git a/desmume/src/frontend/posix/gtk/main.cpp b/desmume/src/frontend/posix/gtk/main.cpp
index b3b004b13..edd4d272f 100644
--- a/desmume/src/frontend/posix/gtk/main.cpp
+++ b/desmume/src/frontend/posix/gtk/main.cpp
@@ -3505,6 +3505,12 @@ int main (int argc, char *argv[])
   my_config.parse(argc, argv);
   init_configured_features( &my_config);
 
+  /* X11 multi-threading support */
+  if(!XInitThreads())
+    {
+      fprintf(stderr, "Warning: X11 not thread-safe\n");
+    }
+
   if (!g_thread_supported())
     g_thread_init( NULL);