Combine sugar, water, syrup, and salt. Cook over low heat; stir until sugar is completely dissolved.
Cook, without stirring, to hard-ball stage (252°).
Beat egg whites until stiff but not dry.
Pour hot syrup slowly over egg whites, beating constantly.
Add vanilla. Beat until mixture loses some of its shine and holds its shape.
Quickly fold in chocolate pieces stirring only enough to mix well.
Drop from tip of spoon onto buttered wax paper.