Create an event queue to store all MirEvents.

This ensures all events come out of the same thread, as well as ensuring
the threads sync up correctly when touching the event queue.

src/mir_window.c

@@ -28,8 +28,66 @@
 #include "xkb_unicode.h"
 
 #include <linux/input.h>
+#include <stdlib.h>
+#include <string.h>
 
 
+typedef struct EventNode
+{
+    TAILQ_ENTRY(EventNode) entries;
+    MirEvent*              event;
+    _GLFWwindow*           window;
+} EventNode;
+
+static void deleteNode(EventQueue* queue, EventNode* node)
+{
+    free(node->event);
+    free(node);
+}
+
+static int emptyEventQueue(EventQueue* queue)
+{
+    return queue->head.tqh_first == NULL ? GL_TRUE : GL_FALSE;
+}
+
+static EventNode* newEventNode(MirEvent const* event, _GLFWwindow* context)
+{
+    EventNode* new_node = calloc(1, sizeof(EventNode));
+    new_node->event     = calloc(1, sizeof(MirEvent));
+    new_node->window    = context;
+
+    memcpy(new_node->event, event, sizeof(MirEvent));
+    return new_node;
+}
+
+static void enqueueEvent(MirEvent const* event, _GLFWwindow* context)
+{
+    pthread_mutex_lock(&_glfw.mir.event_mutex);
+
+    EventNode* new_node = newEventNode(event, context);
+    TAILQ_INSERT_TAIL(&_glfw.mir.event_queue->head, new_node, entries);
+
+    pthread_cond_signal(&_glfw.mir.event_cond);
+
+    pthread_mutex_unlock(&_glfw.mir.event_mutex);
+}
+
+static EventNode* dequeueEvent(EventQueue* queue)
+{
+    EventNode* node = NULL;
+
+    pthread_mutex_lock(&_glfw.mir.event_mutex);
+
+    node = queue->head.tqh_first;
+
+    if (node)
+        TAILQ_REMOVE(&queue->head, node, entries);
+
+    pthread_mutex_unlock(&_glfw.mir.event_mutex);
+
+    return node;
+}
+
 static MirPixelFormat findValidPixelFormat(void)
 {
     unsigned int i, validFormats, size = 32;
@@ -298,21 +356,26 @@ static void handleMotionEvent(const MirMotionEvent motion, _GLFWwindow* window)
         handleMouseEvent(motion, i, window);
 }
 
-static void handleInput(MirSurface* surface, const MirEvent* event, void* context)
+static void handleInput(MirEvent const* event, _GLFWwindow* window)
 {
     switch (event->type)
     {
         case mir_event_type_key:
-            handleKeyEvent(event->key, (_GLFWwindow*) context);
+            handleKeyEvent(event->key, window);
             break;
         case mir_event_type_motion:
-            handleMotionEvent(event->motion, (_GLFWwindow*) context);
+            handleMotionEvent(event->motion, window);
             break;
         default:
             break;
     }
 }
 
+static void addNewEvent(MirSurface* surface, MirEvent const* event, void* context)
+{
+    enqueueEvent(event, context);
+}
+
 static int createSurface(_GLFWwindow* window)
 {
     MirSurfaceParameters params =
@@ -327,7 +390,7 @@ static int createSurface(_GLFWwindow* window)
 
     MirEventDelegate delegate =
     {
-        handleInput,
+        addNewEvent,
         window
     };
 
@@ -353,6 +416,30 @@ static int createSurface(_GLFWwindow* window)
     return GL_TRUE;
 }
 
+//////////////////////////////////////////////////////////////////////////
+//////                       GLFW internal API                      //////
+//////////////////////////////////////////////////////////////////////////
+
+void _glfwInitEventQueue(EventQueue* queue)
+{
+    TAILQ_INIT(&queue->head);
+}
+
+void _glfwDeleteEventQueue(EventQueue* queue)
+{
+    EventNode* node, *node_next;
+    node = queue->head.tqh_first;
+
+    while (node != NULL)
+    {
+        node_next = node->entries.tqe_next;
+
+        TAILQ_REMOVE(&queue->head, node, entries);
+        deleteNode(queue, node);
+
+        node = node_next;
+    }
+}
 
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////
@@ -475,14 +562,25 @@ void _glfwPlatformUnhideWindow(_GLFWwindow* window)
 
 void _glfwPlatformPollEvents(void)
 {
-    // Mir does event handling in a different thread, so windows get events
-    // directly as they happen
+    EventNode* node = NULL;
+
+    while ((node = dequeueEvent(_glfw.mir.event_queue)))
+    {
+        handleInput(node->event, node->window);
+        deleteNode(_glfw.mir.event_queue, node);
+    }
 }
 
 void _glfwPlatformWaitEvents(void)
 {
-    // Mir does event handling in a different thread, so windows get events
-    // directly as they happen
+    pthread_mutex_lock(&_glfw.mir.event_mutex);
+
+    if (emptyEventQueue(_glfw.mir.event_queue))
+        pthread_cond_wait(&_glfw.mir.event_cond, &_glfw.mir.event_mutex);
+
+    pthread_mutex_unlock(&_glfw.mir.event_mutex);
+
+    _glfwPlatformPollEvents();
 }
 
 void _glfwPlatformPostEmptyEvent(void)