diff --git a/sys/Cargo.toml b/sys/Cargo.toml
index 67f619f..fd961be 100644
--- a/sys/Cargo.toml
+++ b/sys/Cargo.toml
@@ -6,6 +6,7 @@ links   = "ffmpeg"
 readme = "README.md"
 authors = ["meh. <meh@schizofreni.co>"]
 license = "WTFPL"
+edition = "2018"
 
 description = "FFI bindings to FFmpeg"
 repository  = "https://github.com/meh/rust-ffmpeg-sys"
diff --git a/sys/build.rs b/sys/build.rs
index 778452e..39950e1 100644
--- a/sys/build.rs
+++ b/sys/build.rs
@@ -1,7 +1,3 @@
-extern crate bindgen;
-extern crate cc;
-extern crate num_cpus;
-extern crate pkg_config;
 
 use std::env;
 use std::fs::{self, File};
diff --git a/sys/src/avutil/error.rs b/sys/src/avutil/error.rs
index cce458c..c3d453d 100644
--- a/sys/src/avutil/error.rs
+++ b/sys/src/avutil/error.rs
@@ -1,4 +1,4 @@
-use libc::{c_char, c_int, size_t};
+use std::os::raw::{c_char, c_int};
 
 // Note: FFmpeg's AVERROR and AVUNERROR are conditionally defined based on
 // whether EDOM is positive, claiming that "Some platforms have E* and errno
@@ -55,7 +55,7 @@ pub const AVERROR_HTTP_SERVER_ERROR: c_int = FFERRTAG!(0xF8, b'5', b'X', b'X');
 #[inline(always)]
 pub unsafe fn av_make_error_string(
     errbuf: *mut c_char,
-    errbuf_size: size_t,
+    errbuf_size: usize,
     errnum: c_int,
 ) -> *mut c_char {
     av_strerror(errnum, errbuf, errbuf_size);
@@ -64,5 +64,5 @@ pub unsafe fn av_make_error_string(
 }
 
 extern "C" {
-    pub fn av_strerror(errnum: c_int, errbuf: *mut c_char, errbuf_size: size_t) -> c_int;
+    pub fn av_strerror(errnum: c_int, errbuf: *mut c_char, errbuf_size: usize) -> c_int;
 }
diff --git a/sys/src/avutil/pixfmt.rs b/sys/src/avutil/pixfmt.rs
index e222ca4..da7c6d5 100644
--- a/sys/src/avutil/pixfmt.rs
+++ b/sys/src/avutil/pixfmt.rs
@@ -1,5 +1,5 @@
-use AVPixelFormat;
-use AVPixelFormat::*;
+use crate::AVPixelFormat;
+use crate::AVPixelFormat::*;
 
 #[cfg(target_endian = "little")]
 pub const AV_PIX_FMT_RGB32: AVPixelFormat = AV_PIX_FMT_BGRA;
diff --git a/sys/src/avutil/rational.rs b/sys/src/avutil/rational.rs
index 7809ee6..fb1a822 100644
--- a/sys/src/avutil/rational.rs
+++ b/sys/src/avutil/rational.rs
@@ -1,5 +1,5 @@
-use libc::{c_double, c_int};
-use AVRational;
+use crate::AVRational;
+use std::os::raw::c_int;
 
 #[inline(always)]
 pub unsafe fn av_make_q(num: c_int, den: c_int) -> AVRational {
@@ -22,7 +22,7 @@ pub unsafe fn av_cmp_q(a: AVRational, b: AVRational) -> c_int {
 }
 
 #[inline(always)]
-pub unsafe fn av_q2d(a: AVRational) -> c_double {
+pub unsafe fn av_q2d(a: AVRational) -> f64 {
     f64::from(a.num) / f64::from(a.den)
 }
 
diff --git a/sys/src/avutil/util.rs b/sys/src/avutil/util.rs
index 49f631d..346d43c 100644
--- a/sys/src/avutil/util.rs
+++ b/sys/src/avutil/util.rs
@@ -1,8 +1,7 @@
-use libc::c_int;
-use {AVRational, AV_TIME_BASE};
+use crate::{AVRational, AV_TIME_BASE};
 
 pub const AV_NOPTS_VALUE: i64 = 0x8000000000000000u64 as i64;
 pub const AV_TIME_BASE_Q: AVRational = AVRational {
     num: 1,
-    den: AV_TIME_BASE as c_int,
+    den: AV_TIME_BASE as _,
 };
diff --git a/sys/src/lib.rs b/sys/src/lib.rs
index 2d8eefa..7a4d1fb 100644
--- a/sys/src/lib.rs
+++ b/sys/src/lib.rs
@@ -12,4 +12,4 @@ include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
 
 #[macro_use]
 mod avutil;
-pub use avutil::*;
+pub use crate::avutil::*;