Auto merge of #2593 - skrap:uclibc-does-not-have-mlock2, r=Amanieu

uclibc does not have mlock2

This fixes the build for the uclibc targets, for example `armv7-unknown-linux-uclibceabihf`.

Author: bors

src/unix/linux_like/linux/gnu/mod.rs

@@ -1336,6 +1336,7 @@ extern "C" {
     pub fn sethostid(hostid: ::c_long) -> ::c_int;
 
     pub fn memfd_create(name: *const ::c_char, flags: ::c_uint) -> ::c_int;
+    pub fn mlock2(addr: *const ::c_void, len: ::size_t, flags: ::c_uint) -> ::c_int;
 }
 
 extern "C" {

src/unix/linux_like/linux/mod.rs

@@ -3534,7 +3534,6 @@ extern "C" {
     pub fn seekdir(dirp: *mut ::DIR, loc: ::c_long);
 
     pub fn telldir(dirp: *mut ::DIR) -> ::c_long;
-    pub fn mlock2(addr: *const ::c_void, len: ::size_t, flags: ::c_uint) -> ::c_int;
     pub fn madvise(addr: *mut ::c_void, len: ::size_t, advice: ::c_int) -> ::c_int;
 
     pub fn msync(addr: *mut ::c_void, len: ::size_t, flags: ::c_int) -> ::c_int;

src/unix/linux_like/linux/musl/mod.rs

@@ -772,6 +772,7 @@ extern "C" {
     pub fn ctermid(s: *mut ::c_char) -> *mut ::c_char;
 
     pub fn memfd_create(name: *const ::c_char, flags: ::c_uint) -> ::c_int;
+    pub fn mlock2(addr: *const ::c_void, len: ::size_t, flags: ::c_uint) -> ::c_int;
 }
 
 cfg_if! {