linux: Add CLOSE_RANGE_* flags

Flags for the SYS_close_range syscall from <linux/close_range.h>.

Author: neocturne

libc-test/build.rs

@@ -2924,6 +2924,10 @@ fn test_linux(target: &str) {
             | "SW_CNT"
                 if mips || ppc64 || riscv64 || sparc64 => true,
 
+            // FIXME: Requires more recent kernel headers (5.9 / 5.11):
+            | "CLOSE_RANGE_UNSHARE"
+            | "CLOSE_RANGE_CLOEXEC" => true,
+
             // kernel constants not available in uclibc 1.0.34
             | "ADDR_COMPAT_LAYOUT"
             | "ADDR_LIMIT_3GB"

libc-test/semver/linux.txt

@@ -265,6 +265,8 @@ CLONE_THREAD
 CLONE_UNTRACED
 CLONE_VFORK
 CLONE_VM
+CLOSE_RANGE_CLOEXEC
+CLOSE_RANGE_UNSHARE
 CMSG_DATA
 CMSG_FIRSTHDR
 CMSG_LEN

src/unix/linux_like/linux/mod.rs

@@ -1818,6 +1818,10 @@ pub const MFD_CLOEXEC: ::c_uint = 0x0001;
 pub const MFD_ALLOW_SEALING: ::c_uint = 0x0002;
 pub const MFD_HUGETLB: ::c_uint = 0x0004;
 
+// linux/close_range.h
+pub const CLOSE_RANGE_UNSHARE: ::c_uint = 1 << 1;
+pub const CLOSE_RANGE_CLOEXEC: ::c_uint = 1 << 2;
+
 // these are used in the p_type field of Elf32_Phdr and Elf64_Phdr, which has
 // the type Elf32Word and Elf64Word respectively. Luckily, both of those are u32
 // so we can use that type here to avoid having to cast.