examples/crypto: fix build on Linux too
examples/crypto: fix build on Linux too

hoheinzollern/FStar,FStarLang/FStar,A-Manning/FStar,MallabaevAzamat/FStar,A-Manning/FStar,YaccConstructor/FStar,YaccConstructor/FStar,YaccConstructor/FStar,MallabaevAzamat/FStar,hoheinzollern/FStar,hoheinzollern/FStar,MallabaevAzamat/FStar,FStarLang/FStar,YaccConstructor/FStar,A-Manning/FStar,hoheinzollern/FStar,MallabaevAzamat/FStar,FStarLang/FStar