Auto merge of #680 - alexcrichton:c_long, r=alexcrichton

Restore SYS_* constants to the c_long type

cc https://github.com/rust-lang/libc/pull/672#issuecomment-316406664

appveyor.yml

 environment:
+  # When this was added there were revocation check failures when using the
+  # libcurl backend as libcurl checks by default, but rustup doesn't provide the
+  # switch to turn this off. Switch to Hyper which looks to not check for
+  # revocation by default like libcurl does.
+  RUSTUP_USE_HYPER: 1
   matrix:
   - TARGET: x86_64-pc-windows-gnu
     MSYS2_BITS: 64