fix(CMakeLists): do not use -fsigned-char
fix(CMakeLists): do not use -fsigned-char

johoelzl/lean,fpvandoorn/lean,leanprover-community/lean,leanprover-community/lean,Kha/lean,digama0/lean,leanprover/lean,johoelzl/lean,leanprover-community/lean,leanprover/lean,digama0/lean,leanprover/lean,johoelzl/lean,leanprover/lean,avigad/lean,leodemoura/lean,leodemoura/lean,fpvandoorn/lean,digama0/lean,leodemoura/lean,leanprover-community/lean,fpvandoorn/lean,Kha/lean,digama0/lean,johoelzl/lean,digama0/lean,Kha/lean,dselsam/lean,fpvandoorn/lean,leanprover-community/lean,johoelzl/lean,dselsam/lean,dselsam/lean,dselsam/lean,leanprover/lean,Kha/lean,avigad/lean,leanprover-community/lean,dselsam/lean,avigad/lean,avigad/lean,fpvandoorn/lean,leodemoura/lean,johoelzl/lean,digama0/lean,Kha/lean,dselsam/lean,fpvandoorn/lean,leanprover/lean,leodemoura/lean,avigad/lean,Kha/lean,leodemoura/lean,avigad/lean