Fix some unsigned/signed comparisons.

common/audio/s9x_sound_driver_pulse.cpp

@@ -191,7 +191,7 @@ bool S9xPulseSoundDriver::write_samples(int16_t *data, int samples)
 
     if (draining)
     {
-        if (bytes > buffer_size / 2)
+        if (bytes > (size_t)buffer_size / 2)
         {
             return false;
         }
@@ -201,13 +201,13 @@ bool S9xPulseSoundDriver::write_samples(int16_t *data, int samples)
         }
     }
 
-    if (samples * 2 > bytes)
+    if ((size_t)samples * 2 > bytes)
     {
         draining = true;
         return false;
     }
 
-    if (samples * 2 < bytes)
+    if ((size_t)samples * 2 < bytes)
         bytes = samples * 2;
 
     if (bytes == 0)

vulkan/vulkan_context.cpp

@@ -205,7 +205,7 @@ bool Context::init_device(int preferred_device)
         return device_list[0];
     };
 
-    if (preferred_device > -1 && preferred_device < device_list.size())
+    if (preferred_device > -1 && (size_t)preferred_device < device_list.size())
         physical_device = device_list[preferred_device];
     else
         physical_device = find_device();

vulkan/vulkan_simple_output.cpp

@@ -55,7 +55,7 @@ SimpleOutput::~SimpleOutput()
 void SimpleOutput::create_objects()
 {
     descriptors.clear();
-    for (size_t i = 0; i < queue_size; i++)
+    for (int i = 0; i < queue_size; i++)
     {
         vk::DescriptorSetAllocateInfo dsai{};
         dsai