Add mallinfo2 support

Author: jonas-schievink

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

@@ -128,6 +128,19 @@ s! {
         pub keepcost: ::c_int,
     }
 
+    pub struct mallinfo2 {
+        pub arena: ::size_t,
+        pub ordblks: ::size_t,
+        pub smblks: ::size_t,
+        pub hblks: ::size_t,
+        pub hblkhd: ::size_t,
+        pub usmblks: ::size_t,
+        pub fsmblks: ::size_t,
+        pub uordblks: ::size_t,
+        pub fordblks: ::size_t,
+        pub keepcost: ::size_t,
+    }
+
     pub struct nlmsghdr {
         pub nlmsg_len: u32,
         pub nlmsg_type: u16,
@@ -1281,6 +1294,7 @@ extern "C" {
     ) -> ::c_int;
     pub fn sched_getcpu() -> ::c_int;
     pub fn mallinfo() -> ::mallinfo;
+    pub fn mallinfo2() -> ::mallinfo2;
     pub fn malloc_usable_size(ptr: *mut ::c_void) -> ::size_t;
     pub fn getpwent_r(
         pwd: *mut ::passwd,