Fixed bug 4526 - replace SDL_RW* macros with functions for using in bindings

ace

I got this bug in SDL_ttf:
https://bugzilla.libsdl.org/show_bug.cgi?id=4524
Sylvain proposed solution:
SDL_RWseek(RWops, 0, RW_SEEK_SET);

And it works, but i can use it my project, because it written in C# with SDL2-CS wrapper and there not export for macroses:
#define SDL_RWsize(ctx)         (ctx)->size(ctx)
#define SDL_RWseek(ctx, offset, whence) (ctx)->seek(ctx, offset, whence)
#define SDL_RWtell(ctx)         (ctx)->seek(ctx, 0, RW_SEEK_CUR)
#define SDL_RWread(ctx, ptr, size, n)   (ctx)->read(ctx, ptr, size, n)
#define SDL_RWwrite(ctx, ptr, size, n)  (ctx)->write(ctx, ptr, size, n)
#define SDL_RWclose(ctx)        (ctx)->close(ctx)

Therefore, I suggest replacing this macros with functions so that they can be exported and used in bindings

src/file/SDL_rwops.c

@@ -752,6 +752,48 @@ done:
     return data;
 }
 
+void *
+SDL_LoadFile(const char *file, size_t *datasize)
+{
+   return SDL_LoadFile_RW(SDL_RWFromFile(file, "rb"), datasize, 1);
+}
+
+Sint64
+SDL_RWsize(SDL_RWops *context)
+{
+    return context->size(context);
+}
+
+Sint64
+SDL_RWseek(SDL_RWops *context, Sint64 offset, int whence)
+{
+    return context->seek(context, offset, whence);
+}
+
+Sint64
+SDL_RWtell(SDL_RWops *context)
+{
+    return context->seek(context, 0, RW_SEEK_CUR);
+}
+
+size_t
+SDL_RWread(SDL_RWops *context, void *ptr, size_t size, size_t maxnum)
+{
+    return context->read(context, ptr, size, maxnum);
+}
+
+size_t
+SDL_RWwrite(SDL_RWops *context, const void *ptr, size_t size, size_t num)
+{
+    return context->write(context, ptr, size, num);
+}
+
+int
+SDL_RWclose(SDL_RWops *context)
+{
+    return context->close(context);
+}
+
 /* Functions for dynamically reading and writing endian-specific values */
 
 Uint8