```
./src/thread/pthread/SDL_syssem.c:140:12: warning: variable 'retval' is used uninitialized whenever 'while' loop exits because its condition is false [-Wsometimes-uninitialized]
while (sem_trywait(&sem->sem) != 0) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~
./src/thread/pthread/SDL_syssem.c:149:12: note: uninitialized use occurs here
return retval;
^~~~~~
./src/thread/pthread/SDL_syssem.c:140:12: note: remove the condition if it is always true
while (sem_trywait(&sem->sem) != 0) {
```
This was a legitimate bug, thank you clang!
Fixes https://github.com/libsdl-org/SDL/issues/6830
(cherry picked from commit b678a98024)
```
./src/joystick/SDL_joystick.c:105:12: warning: no previous extern declaration for non-static variable 'SDL_joystick_lock' [-Wmissing-variable-declarations]
SDL_mutex *SDL_joystick_lock = NULL; /* This needs to support recursive locks */
^
./src/joystick/SDL_joystick.c:105:1: note: declare 'static' if the variable is not intended to be used outside of this translation unit
SDL_mutex *SDL_joystick_lock = NULL; /* This needs to support recursive locks */
^
```
1 warning generated.
The annotations have been added to SDL_mutex.h and have been made public so applications can enable this for their own code.
Clang assumes that locking and unlocking can't fail, but SDL has the concept of a NULL mutex, so the mutex functions have been changed not to report errors if a mutex hasn't been initialized. We do have mutexes that might be accessed when they are NULL, notably in the event system, so this is an important change.
This commit cleans up a bunch of rare race conditions in the joystick and game controller code so now everything should be completely protected by the joystick lock.
To test this, change the compiler to "clang -Wthread-safety -Werror=thread-safety -DSDL_THREAD_SAFETY_ANALYSIS"
It was previously thought that these function calls were unnecessary as the initial bug and reproduction case that necessitated their addition seemed to be fixed, but apparently there are still cases where this needs to be set explicitly. Set the xdg surface geometry at creation time and when the window size changes.
Partially reverts #6361. This is not needed in the libdecor path, as libdecor calls this for the content surface internally.
(cherry picked from commit 90a964f132)
Num Lock and Caps Lock always need to be explicitly handled by the modifier handler function, or they won't be correctly set if active at application startup, or if the lock state is changed while the application lacks focus since a key press for these keys will never be received. In these cases, the internal SDL modifier state can end up the inverse of the actual modifier state.
(cherry picked from commit 653e484da1)
