Index: ctor/Cargo.toml
===================================================================
--- ctor.orig/Cargo.toml
+++ ctor/Cargo.toml
@@ -32,16 +32,11 @@ version = "1.0.20"
 
 [dependencies.syn]
 version = "1.0.98"
-features = [
-    "full",
-    "parsing",
-    "printing",
-    "proc-macro",
-]
+features = ["full", "parsing", "printing", "proc-macro"]
 default-features = false
 
 [dev-dependencies.libc-print]
-version = "0.1.20"
+version = ">=0.1.20,<0.6"
 
 [badges.travis-ci]
 branch = "master"
