Add Emscripten example.

examples/build/mal_build_examples_emscripten.bat

+emcc ../simple_playback_emscripten.c -o ../bin/simple_playback_emscripten.html
\ No newline at end of file

examples/simple_playback_emscripten.c

+#define MAL_IMPLEMENTATION
+#include "../mini_al.h"
+
+#include <stdio.h>
+
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+
+void main_loop__em()
+{
+}
+#endif
+
+#define DEVICE_FORMAT       mal_format_f32
+#define DEVICE_CHANNELS     1
+#define DEVICE_SAMPLE_RATE  48000
+
+// This is the function that's used for sending more data to the device for playback.
+mal_uint32 on_send_frames_to_device(mal_device* pDevice, mal_uint32 frameCount, void* pSamples)
+{
+    mal_assert(pDevice->channels == DEVICE_CHANNELS);
+
+    mal_sine_wave* pSineWave = (mal_sine_wave*)pDevice->pUserData;
+    mal_assert(pSineWave != NULL);
+
+    return mal_sine_wave_read(pSineWave, frameCount, (float*)pSamples);
+}
+
+int main(int argc, char** argv)
+{
+    (void)argc;
+    (void)argv;
+
+    mal_sine_wave sineWave;
+    mal_sine_wave_init(0.2, 400, DEVICE_SAMPLE_RATE, &sineWave);
+    
+    mal_device_config config = mal_device_config_init_playback(DEVICE_FORMAT, DEVICE_CHANNELS, DEVICE_SAMPLE_RATE, on_send_frames_to_device);
+    mal_device device;
+    if (mal_device_init(NULL, mal_device_type_playback, NULL, &config, &sineWave, &device) != MAL_SUCCESS) {
+        printf("Failed to open playback device.\n");
+        return -4;
+    }
+
+    printf("Device Name: %s\n", device.name);
+
+    if (mal_device_start(&device) != MAL_SUCCESS) {
+        printf("Failed to start playback device.\n");
+        mal_device_uninit(&device);
+        return -5;
+    }
+    
+#ifdef __EMSCRIPTEN__
+    emscripten_set_main_loop(main_loop__em, 0, 1);
+#else
+    printf("Press Enter to quit...\n");
+    getchar();
+#endif
+    
+    mal_device_uninit(&device);
+    
+    return 0;
+}