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/stdlib/SDL_malloc.c

@@ -5287,7 +5287,10 @@ void *SDL_malloc(size_t size)
     mem = s_mem.malloc_func(size);
     if (mem) {
         SDL_AtomicIncRef(&s_mem.num_allocations);
+    } else {
+        SDL_OutOfMemory();
     }
+
     return mem;
 }
 
@@ -5303,7 +5306,10 @@ void *SDL_calloc(size_t nmemb, size_t size)
     mem = s_mem.calloc_func(nmemb, size);
     if (mem) {
         SDL_AtomicIncRef(&s_mem.num_allocations);
+    } else {
+        SDL_OutOfMemory();
     }
+
     return mem;
 }
 
@@ -5318,7 +5324,10 @@ void *SDL_realloc(void *ptr, size_t size)
     mem = s_mem.realloc_func(ptr, size);
     if (mem && !ptr) {
         SDL_AtomicIncRef(&s_mem.num_allocations);
+    } else if (!mem) {
+        SDL_OutOfMemory();
     }
+
     return mem;
 }