Don't link util on musl, consolidate #[link]

Author: alexcrichton

src/unix/notbsd/linux/mips.rs

@@ -502,6 +502,7 @@ pub const RTLD_NOLOAD: ::c_int = 0x8;
 
 pub const SYS_gettid: ::c_long = 4222;   // Valid for O32
 
+#[link(name = "util")]
 extern {
     pub fn sysctl(name: *mut ::c_int,
                   namelen: ::c_int,

src/unix/notbsd/linux/mod.rs

@@ -478,7 +478,6 @@ extern {
     static mut program_invocation_short_name: *mut ::c_char;
 }
 
-#[link(name = "util")]
 extern {
     pub fn shm_open(name: *const c_char, oflag: ::c_int,
                     mode: mode_t) -> ::c_int;

src/unix/notbsd/linux/other/mod.rs

@@ -469,6 +469,7 @@ cfg_if! {
     }
 }
 
+#[link(name = "util")]
 extern {
     pub fn sysctl(name: *mut ::c_int,
                   namelen: ::c_int,