Use clang-sys bindings instead of ours.

I plan to use a dynamically loaded clang-sys library to remove the llvm-stable
feature.

This is part of the work.

Author: emilio

libbindgen/Cargo.toml

@@ -25,13 +25,13 @@ quasi_codegen = "0.26"
 
 [dependencies]
 cfg-if = "0.1.0"
-clang-sys = "0.11.1"
 lazy_static = "0.1.*"
 libc = "0.2"
 rustc-serialize = "0.3.19"
 syntex_syntax = "0.50"
 regex = "0.1"
 cexpr = "0.2"
+clang-sys = { version = "0.11.1", features = ["gte_clang_3_6", "gte_clang_3_7", "gte_clang_3_8", "gte_clang_3_9"] }
 
 [dependencies.aster]
 features = ["with-syntex"]