Add f16 and rtm target feature features

Author: pepyakin

src/libcore/lib.rs

@@ -115,6 +115,8 @@
 #![feature(wasm_target_feature)]
 #![feature(avx512_target_feature)]
 #![feature(cmpxchg16b_target_feature)]
+#![feature(f16c_target_feature)]
+#![feature(rtm_target_feature)]
 #![feature(const_slice_len)]
 #![feature(const_str_as_bytes)]
 #![feature(const_str_len)]