SYNC_* constants should be unsigned (to reflect usage).
diff --git a/src/unix/notbsd/linux/mod.rs b/src/unix/notbsd/linux/mod.rs
index bbe4360..fbe0e67 100644
--- a/src/unix/notbsd/linux/mod.rs
+++ b/src/unix/notbsd/linux/mod.rs
@@ -479,9 +479,9 @@
pub const RB_SW_SUSPEND: ::c_int = 0xd000fce2u32 as i32;
pub const RB_KEXEC: ::c_int = 0x45584543u32 as i32;
-pub const SYNC_FILE_RANGE_WAIT_BEFORE: ::c_int = 1;
-pub const SYNC_FILE_RANGE_WRITE: ::c_int = 2;
-pub const SYNC_FILE_RANGE_WAIT_AFTER: ::c_int = 4;
+pub const SYNC_FILE_RANGE_WAIT_BEFORE: ::c_uint = 1;
+pub const SYNC_FILE_RANGE_WRITE: ::c_uint = 2;
+pub const SYNC_FILE_RANGE_WAIT_AFTER: ::c_uint = 4;
f! {
pub fn CPU_ZERO(cpuset: &mut cpu_set_t) -> () {