cmake: dfix disabling dlopen notes when configuring with -DSDL_DLOPEN_NOTES=OFF

CMakeLists.txt

@@ -1786,6 +1786,7 @@ elseif(EMSCRIPTEN)
 
 elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
 
+  set(SDL_DISABLE_DLOPEN_NOTES TRUE)
   if(SDL_DLOPEN_NOTES)
     set(CHECK_ELF_DLNOTES_SRC [==[
     #ifndef __ELF__
@@ -1798,10 +1799,10 @@ elseif(UNIX AND NOT APPLE AND NOT RISCOS AND NOT HAIKU)
       return argc + dlnote.hdr.a;
     }
     ]==])
-    set(SDL_DISABLE_DLOPEN_NOTES FALSE)
     check_c_source_compiles("${CHECK_ELF_DLNOTES_SRC}" COMPILER_SUPPORTS_ELFNOTES)
-    if(NOT COMPILER_SUPPORTS_ELFNOTES)
-      set(SDL_DISABLE_DLOPEN_NOTES TRUE)
+    if(COMPILER_SUPPORTS_ELFNOTES)
+      set(SDL_DISABLE_DLOPEN_NOTES FALSE)
+      set(HAVE_DLOPEN_NOTES TRUE)
     endif()
   endif()