linux: Changed internal functions to be static.

src/core/linux/SDL_evdev.c

@@ -110,7 +110,7 @@ static int SDL_EVDEV_device_removed(const char *dev_path);
 
 #if SDL_USE_LIBUDEV
 static int SDL_EVDEV_device_added(const char *dev_path, int udev_class);
-void SDL_EVDEV_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class,
+static void SDL_EVDEV_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class,
     const char *dev_path);
 #endif /* SDL_USE_LIBUDEV */
 
@@ -195,7 +195,7 @@ SDL_EVDEV_Quit(void)
 }
 
 #if SDL_USE_LIBUDEV
-void SDL_EVDEV_udev_callback(SDL_UDEV_deviceevent udev_event, int udev_class,
+static void SDL_EVDEV_udev_callback(SDL_UDEV_deviceevent udev_event, int udev_class,
     const char* dev_path)
 {
     if (dev_path == NULL) {

src/haptic/linux/SDL_syshaptic.c

@@ -49,7 +49,7 @@
 static int MaybeAddDevice(const char *path);
 #if SDL_USE_LIBUDEV
 static int MaybeRemoveDevice(const char *path);
-void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
+static void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
 #endif /* SDL_USE_LIBUDEV */
 
 /*
@@ -211,7 +211,7 @@ HapticByDevIndex(int device_index)
 }
 
 #if SDL_USE_LIBUDEV
-void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
+static void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
 {
     if (devpath == NULL || !(udev_class & SDL_UDEV_DEVICE_JOYSTICK)) {
         return;

src/joystick/linux/SDL_sysjoystick.c

@@ -52,7 +52,7 @@
 static int MaybeAddDevice(const char *path);
 #if SDL_USE_LIBUDEV
 static int MaybeRemoveDevice(const char *path);
-void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
+static void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
 #endif /* SDL_USE_LIBUDEV */
 
 
@@ -237,7 +237,7 @@ IsJoystick(int fd, char *namebuf, const size_t namebuflen, SDL_JoystickGUID *gui
 }
 
 #if SDL_USE_LIBUDEV
-void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
+static void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
 {
     if (devpath == NULL) {
         return;