Adding MAP_DROPPABLE for Linux (6.11)

ref: https://github.com/torvalds/linux/blob/feffde684ac29a3b7aec82d2df850fbdbdee55e4/include/uapi/linux/mman.h#L20

(backport <#4173>)
(cherry picked from commit 40a4d33)

Author: devnexen

libc-test/build.rs

@@ -4321,6 +4321,9 @@ fn test_linux(target: &str) {
             "EPIOCSPARAMS"
             | "EPIOCGPARAMS" => true,
 
+            // FIXME: Requires >= 6.11 kernel headers.
+            "MAP_DROPPABLE" => true,
+
             _ => false,
         }
     });

libc-test/semver/linux.txt

@@ -1586,6 +1586,7 @@ MADV_UNMERGEABLE
 MADV_WILLNEED
 MADV_WIPEONFORK
 MAP_DENYWRITE
+MAP_DROPPABLE
 MAP_EXECUTABLE
 MAP_FILE
 MAP_FIXED_NOREPLACE

src/unix/linux_like/linux/mod.rs

@@ -4730,6 +4730,7 @@ pub const UDP_NO_CHECK6_RX: c_int = 102;
 
 // include/uapi/linux/mman.h
 pub const MAP_SHARED_VALIDATE: c_int = 0x3;
+pub const MAP_DROPPABLE: c_int = 0x8;
 
 // include/uapi/asm-generic/mman-common.h
 pub const MAP_FIXED_NOREPLACE: c_int = 0x100000;