fix compiler errors and warnings

Problems that were fixed:
  - gcc crate deprecated compile_library
  - `cargo test -p kvm` had a compile error
  - `cargo test -p kvm_sys` failed to link with libc
  - main.rs failed to include `getpid` and had dead code
  - fork.rs had a warning in `cargo test -p sys_util`
  - unused const in serial.rs

BUG=None
TEST=sudo cargo test -p data_model -p io_jail -p kernel_loader -p kvm \
     -p kvm_sys -p net_sys -p net_util -p syscall_defines -p sys_util \
     -p virtio_sys -p vhost -p x86_64 -p crosvm

Change-Id: Iaf0389013fbcdfbfaa7cf37ea1a1fc045f480ada
Reviewed-on: https://chromium-review.googlesource.com/642509
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Jason Clinton <jclinton@chromium.org>
Reviewed-by: Stephen Barber <smbarber@chromium.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/src/main.rs b/src/main.rs
index 5cc9532..63819a1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -23,7 +23,7 @@ pub mod kernel_cmdline;
 pub mod vm_control;
 pub mod device_manager;
 
-use std::ffi::{OsString, CString, CStr};
+use std::ffi::{CString, CStr};
 use std::fmt;
 use std::fs::File;
 use std::fs::OpenOptions;
@@ -42,7 +42,8 @@ use clap::{Arg, App, SubCommand};
 use io_jail::Minijail;
 use kvm::*;
 use sys_util::{GuestAddress, GuestMemory, EventFd, TempDir, Terminal, Poller, Pollable, Scm,
-               register_signal_handler, Killable, SignalFd, kill_process_group, reap_child, syslog};
+               register_signal_handler, Killable, SignalFd, getpid, kill_process_group, reap_child,
+               syslog};
 
 use device_manager::*;
 use vm_control::{VmRequest, VmResponse};
@@ -62,7 +63,6 @@ enum Error {
     RegisterBlock(device_manager::Error),
     RegisterNet(device_manager::Error),
     Cmdline(kernel_cmdline::Error),
-    RegisterIoevent(sys_util::Error),
     RegisterIrqfd(sys_util::Error),
     RegisterRng(device_manager::Error),
     RngDeviceNew(hw::virtio::RngError),
@@ -121,7 +121,6 @@ impl fmt::Display for Error {
                 write!(f, "failed to create root directory for a rng device: {:?}", e)
             }
             &Error::Cmdline(ref e) => write!(f, "the given kernel command line was invalid: {}", e),
-            &Error::RegisterIoevent(ref e) => write!(f, "error registering ioevent: {:?}", e),
             &Error::RegisterIrqfd(ref e) => write!(f, "error registering irqfd: {:?}", e),
             &Error::KernelLoader(ref e) => write!(f, "error loading kernel: {:?}", e),
             &Error::ConfigureSystem(ref e) => write!(f, "error configuring system: {:?}", e),