Renamed DECLSPEC to SDL_DECLSPEC

docs/README-documentation-rules.md

@@ -57,7 +57,7 @@ standard comment format:
  *
  * \sa SDL_DoSomethingElse
  */
-extern DECLSPEC int SDLCALL SDL_DoSomething(int frozzlevel, int color);
+extern SDL_DECLSPEC int SDLCALL SDL_DoSomething(int frozzlevel, int color);
 ```
 
 Note the `/**` at the start of the comment. That's a "Doxygen-style" comment,

docs/doxyfile

@@ -1297,7 +1297,7 @@ INCLUDE_FILE_PATTERNS  =
 # instead of the = operator.
 
 PREDEFINED             = DOXYGEN_SHOULD_IGNORE_THIS=1 \
-                         DECLSPEC= \
+                         SDL_DECLSPEC= \
                          SDLCALL= \
                          _WIN32=1