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/generic/SDL_syscond.c

@@ -64,8 +64,6 @@ SDL_Condition *SDL_CreateCondition_generic(void)
             SDL_DestroyCondition_generic((SDL_Condition *)cond);
             cond = NULL;
         }
-    } else {
-        SDL_OutOfMemory();
     }
     return (SDL_Condition *)cond;
 }

src/thread/generic/SDL_sysmutex.c

@@ -45,8 +45,6 @@ SDL_Mutex *SDL_CreateMutex(void)
             SDL_free(mutex);
             mutex = NULL;
         }
-    } else {
-        SDL_OutOfMemory();
     }
 #endif // !SDL_THREADS_DISABLED
 

src/thread/generic/SDL_sysrwlock.c

@@ -59,7 +59,6 @@ SDL_RWLock *SDL_CreateRWLock_generic(void)
     SDL_RWLock *rwlock = (SDL_RWLock *) SDL_calloc(1, sizeof (*rwlock));
 
     if (!rwlock) {
-        SDL_OutOfMemory();
         return NULL;
     }
 

src/thread/generic/SDL_syssem.c

@@ -67,7 +67,6 @@ SDL_Semaphore *SDL_CreateSemaphore(Uint32 initial_value)
 
     sem = (SDL_Semaphore *)SDL_malloc(sizeof(*sem));
     if (!sem) {
-        SDL_OutOfMemory();
         return NULL;
     }
     sem->count = initial_value;