Ghilas, who has scored 11 goals in the Portuguese top flight this term, is thought to be on the radar of the Toffees, as well as Ligue 1 club Marseille.
The 22-year-old is also believed to have attracted the interest of Sporting Lisbon but reports suggest he would rather make an overseas move.
The striker is pleased to be linked with clubs abroad but says he will wait and see if there is any foundation to the rumours.
He said: "There is interest from clubs but I will decide at the end of the season.
"Everton? I have heard about that in the papers. They are a very good team and a big club so it is flattering. Let's wait and see if it is real interest at the end of the season.
"Marseille would also be fantastic but let's wait and see."