Papers3 improvements (#611)

- And Tab5 keyboard improvements
- Usb host keyboard improvements
- Symbols
- Requires the device.py change from CL-32 PR but that only affects visuals and not build breaking

TactilityKernel/source/drivers/keyboard.cpp

@@ -9,6 +9,12 @@ extern "C" {
 
 error_t keyboard_read_key(Device* device, KeyboardKeyData* data) {
     const auto* driver = device_get_driver(device);
+
+    // Default the modifier fields here rather than in each driver: only drivers whose hardware can
+    // report modifiers set them, and the rest would otherwise leave whatever the caller's stack held.
+    data->ctrl = false;
+    data->alt = false;
+
     return KEYBOARD_DRIVER_API(driver)->read_key(device, data);
 }
 

TactilityKernel/source/symbols.c

@@ -171,6 +171,7 @@ const struct ModuleSymbol KERNEL_SYMBOLS[] = {
     DEFINE_MODULE_SYMBOL(file_system_unmount),
     DEFINE_MODULE_SYMBOL(file_system_is_mounted),
     DEFINE_MODULE_SYMBOL(file_system_get_path),
+    DEFINE_MODULE_SYMBOL(file_system_for_each),
     // memory
     DEFINE_MODULE_SYMBOL(MEMORY_POLICY_DEFAULT),
     DEFINE_MODULE_SYMBOL(memory_print_stats),