configure: Fix notice message for libSDL2.

configure

@@ -13227,7 +13227,7 @@ test -z "$SDL2_CFLAGS" || SDL2_CFLAGS=`echo " $SDL2_CFLAGS" | sed 's/ -I\([^/]\)
 test -z "$SDL2_LIBS" || SDL2_LIBS=`echo " $SDL2_LIBS" | sed 's/ -L\([^/]\)/ -L\$(top_builddir)\/\1/g'`
 
 fi
-if test "x$SDL_LIBS" = "x"; then :
+if test "x$ac_cv_lib_soname_SDL2" = "x"; then :
   case "x$with_sdl" in
   x)   as_fn_append wine_notices "|libSDL2 ${notice_platform}development files not found, SDL2 won't be supported." ;;
   xno) ;;

configure.ac

@@ -1601,7 +1601,7 @@ then
         [AC_CHECK_HEADERS([SDL2/SDL.h],
             [WINE_CHECK_SONAME(SDL2,SDL_Init,,,,[[libSDL2-2.0*]])])])
 fi
-WINE_NOTICE_WITH(sdl,[test "x$SDL_LIBS" = "x"],
+WINE_NOTICE_WITH(sdl,[test "x$ac_cv_lib_soname_SDL2" = "x"],
                  [libSDL2 ${notice_platform}development files not found, SDL2 won't be supported.])
 
 dnl **** Check for capi4linux ****