error: SDL's allocators now call SDL_OutOfMemory on error.

This means the allocator's caller doesn't need to use SDL_OutOfMemory directly
if the allocation fails.

This applies to the usual allocators: SDL_malloc, SDL_calloc, SDL_realloc
(all of these regardless of if the app supplied a custom allocator or we're
using system malloc() or an internal copy of dlmalloc under the hood),
SDL_aligned_alloc, SDL_small_alloc, SDL_strdup, SDL_asprintf, SDL_wcsdup...
probably others. If it returns something you can pass to SDL_free, it should
work.

The caller might still need to use SDL_OutOfMemory if something that wasn't
SDL allocated the memory: operator new in C++ code, Objective-C's alloc
message, win32 GlobalAlloc, etc.

Fixes #8642.

src/thread/windows/SDL_syscond_cv.c

@@ -80,23 +80,14 @@ typedef struct SDL_cond_cv
 
 static SDL_Condition *SDL_CreateCondition_cv(void)
 {
-    SDL_cond_cv *cond;
-
     /* Relies on CONDITION_VARIABLE_INIT == 0. */
-    cond = (SDL_cond_cv *)SDL_calloc(1, sizeof(*cond));
-    if (!cond) {
-        SDL_OutOfMemory();
-    }
-
-    return (SDL_Condition *)cond;
+    return (SDL_Condition *)SDL_calloc(1, sizeof(SDL_cond_cv));
 }
 
 static void SDL_DestroyCondition_cv(SDL_Condition *cond)
 {
-    if (cond) {
-        /* There are no kernel allocated resources */
-        SDL_free(cond);
-    }
+    /* There are no kernel allocated resources */
+    SDL_free(cond);
 }
 
 static int SDL_SignalCondition_cv(SDL_Condition *_cond)

src/thread/windows/SDL_sysmutex.c

@@ -58,15 +58,10 @@ static pfnTryAcquireSRWLockExclusive pTryAcquireSRWLockExclusive = NULL;
 
 static SDL_Mutex *SDL_CreateMutex_srw(void)
 {
-    SDL_mutex_srw *mutex;
-
-    mutex = (SDL_mutex_srw *)SDL_calloc(1, sizeof(*mutex));
-    if (!mutex) {
-        SDL_OutOfMemory();
+    SDL_mutex_srw *mutex = (SDL_mutex_srw *)SDL_calloc(1, sizeof(*mutex));
+    if (mutex) {
+        pInitializeSRWLock(&mutex->srw);
     }
-
-    pInitializeSRWLock(&mutex->srw);
-
     return (SDL_Mutex *)mutex;
 }
 
@@ -153,8 +148,6 @@ static SDL_Mutex *SDL_CreateMutex_cs(void)
 #else
         InitializeCriticalSectionAndSpinCount(&mutex->cs, 2000);
 #endif
-    } else {
-        SDL_OutOfMemory();
     }
     return (SDL_Mutex *)mutex;
 }

src/thread/windows/SDL_sysrwlock_srw.c

@@ -88,10 +88,9 @@ typedef struct SDL_rwlock_srw
 static SDL_RWLock *SDL_CreateRWLock_srw(void)
 {
     SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *)SDL_calloc(1, sizeof(*rwlock));
-    if (!rwlock) {
-        SDL_OutOfMemory();
+    if (rwlock) {
+        pInitializeSRWLock(&rwlock->srw);
     }
-    pInitializeSRWLock(&rwlock->srw);
     return (SDL_RWLock *)rwlock;
 }
 

src/thread/windows/SDL_syssem.c

@@ -85,17 +85,13 @@ static SDL_Semaphore *SDL_CreateSemaphore_atom(Uint32 initial_value)
     sem = (SDL_sem_atom *)SDL_malloc(sizeof(*sem));
     if (sem) {
         sem->count = initial_value;
-    } else {
-        SDL_OutOfMemory();
     }
     return (SDL_Semaphore *)sem;
 }
 
 static void SDL_DestroySemaphore_atom(SDL_Semaphore *sem)
 {
-    if (sem) {
-        SDL_free(sem);
-    }
+    SDL_free(sem);
 }
 
 static int SDL_WaitSemaphoreTimeoutNS_atom(SDL_Semaphore *_sem, Sint64 timeoutNS)
@@ -226,6 +222,7 @@ static SDL_Semaphore *SDL_CreateSemaphore_kern(Uint32 initial_value)
     sem = (SDL_sem_kern *)SDL_malloc(sizeof(*sem));
     if (sem) {
         /* Create the semaphore, with max value 32K */
+// !!! FIXME: CreateSemaphoreEx is available in Vista and later, so if XP support is dropped, we can lose this #ifdef.
 #ifdef __WINRT__
         sem->id = CreateSemaphoreEx(NULL, initial_value, 32 * 1024, NULL, 0, SEMAPHORE_ALL_ACCESS);
 #else
@@ -237,8 +234,6 @@ static SDL_Semaphore *SDL_CreateSemaphore_kern(Uint32 initial_value)
             SDL_free(sem);
             sem = NULL;
         }
-    } else {
-        SDL_OutOfMemory();
     }
     return (SDL_Semaphore *)sem;
 }