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/misc/windows/SDL_sysurl.c

@@ -47,7 +47,7 @@ int SDL_SYS_OpenURL(const char *url)
     wurl = WIN_UTF8ToStringW(url);
     if (!wurl) {
         WIN_CoUninitialize();
-        return SDL_OutOfMemory();
+        return -1;
     }
 
     /* Success returns value greater than 32. Less is an error. */

src/misc/winrt/SDL_sysurl.cpp

@@ -27,7 +27,7 @@ int SDL_SYS_OpenURL(const char *url)
 {
     WCHAR *wurl = WIN_UTF8ToStringW(url);
     if (!wurl) {
-        return SDL_OutOfMemory();
+        return -1;
     }
     auto strurl = ref new Platform::String(wurl);
     SDL_free(wurl);