Auto merge of #1048 - ColinFinck:master, r=alexcrichton

Add libc definitions for HermitCore (https://hermitcore.org)

HermitCore is based on lwIP, newlib, and pthread-embedded.
Some definitions are similar to other targets using newlib, however some are different enough to justify an own "hermit" port and not base on the existing "newlib" port.

Author: bors

src/unix/hermit/aarch64.rs

@@ -0,0 +1,2 @@
+pub type c_char = u8;
+pub type wchar_t = u32;