CI: Add NetBSD target (#180)

* Remove the `sys-info` crate

It offers much more features than we currently use.

Additionally, it was preventing me to cross-compile for NetBSD.

Since we were just using the `hostname()` function from the crate,
I went ahead and stole it.

* Add NetBSD target

* Fix FreeBSD clippy warnings

src/utils.rs

@@ -107,3 +107,55 @@ pub fn require_option<T>(option: Option<T>, cause: String) -> Result<T> {
         Err(SkipStep(cause).into())
     }
 }
+
+/* sys-info-rs
+ *
+ * Copyright (c) 2015 Siyu Wang
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#[cfg(target_family = "unix")]
+pub fn hostname() -> Result<String> {
+    use std::ffi;
+    extern crate libc;
+
+    unsafe {
+        let buf_size = libc::sysconf(libc::_SC_HOST_NAME_MAX) as usize;
+        let mut buf = Vec::<u8>::with_capacity(buf_size + 1);
+
+        if libc::gethostname(buf.as_mut_ptr() as *mut libc::c_char, buf_size) < 0 {
+            return Err(SkipStep(format!("Failed to get hostname: {}", std::io::Error::last_os_error())).into());
+        }
+        let hostname_len = libc::strnlen(buf.as_ptr() as *const libc::c_char, buf_size);
+        buf.set_len(hostname_len);
+
+        Ok(ffi::CString::new(buf).unwrap().into_string().unwrap())
+    }
+}
+
+#[cfg(target_family = "windows")]
+pub fn hostname() -> Result<String> {
+    use crate::command::CommandExt;
+    use std::process::Command;
+
+    Command::new("hostname")
+        .output_checked_utf8()
+        .map_err(|err| SkipStep(format!("Failed to get hostname: {}", err)).into())
+        .map(|output| output.stdout.trim().to_owned())
+}