Update libc dependency to 0.2.156. (#1065)

Author: ur4t

Cargo.toml

@@ -38,15 +38,15 @@ once_cell = { version = "1.5.2", optional = true }
 [target.'cfg(all(not(rustix_use_libc), not(miri), target_os = "linux", target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "riscv64", all(rustix_use_experimental_asm, target_arch = "powerpc64"), all(rustix_use_experimental_asm, target_arch = "mips"), all(rustix_use_experimental_asm, target_arch = "mips32r6"), all(rustix_use_experimental_asm, target_arch = "mips64"), all(rustix_use_experimental_asm, target_arch = "mips64r6"), target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64"))))'.dependencies]
 linux-raw-sys = { version = "0.4.14", default-features = false, features = ["general", "errno", "ioctl", "no_std", "elf"] }
 libc_errno = { package = "errno", version = "0.3.8", default-features = false, optional = true }
-libc = { version = "0.2.153", default-features = false, optional = true }
+libc = { version = "0.2.156", default-features = false, optional = true }
 
 # Dependencies for platforms where only libc is supported:
 #
 # On all other Unix-family platforms, and under Miri, we always use the libc
 # backend, so enable its dependencies unconditionally.
 [target.'cfg(all(not(windows), any(rustix_use_libc, miri, not(all(target_os = "linux", target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "riscv64", all(rustix_use_experimental_asm, target_arch = "powerpc64"), all(rustix_use_experimental_asm, target_arch = "mips"), all(rustix_use_experimental_asm, target_arch = "mips32r6"), all(rustix_use_experimental_asm, target_arch = "mips64"), all(rustix_use_experimental_asm, target_arch = "mips64r6"), target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64")))))))'.dependencies]
 libc_errno = { package = "errno", version = "0.3.8", default-features = false }
-libc = { version = "0.2.153", default-features = false }
+libc = { version = "0.2.156", default-features = false }
 
 # Additional dependencies for Linux with the libc backend:
 #
@@ -74,7 +74,7 @@ default-features = false
 
 [dev-dependencies]
 tempfile = "3.5.0"
-libc = "0.2.153"
+libc = "0.2.156"
 libc_errno = { package = "errno", version = "0.3.8", default-features = false }
 serial_test = "2.0.0"
 memoffset = "0.9.0"

src/backend/libc/param/auxv.rs

@@ -46,10 +46,8 @@ pub(crate) fn linux_hwcap() -> (usize, usize) {
 ))]
 #[inline]
 pub(crate) fn linux_minsigstksz() -> usize {
-    // FIXME: reuse const from libc when available?
-    const AT_MINSIGSTKSZ: c::c_ulong = 51;
     if let Some(libc_getauxval) = getauxval.get() {
-        unsafe { libc_getauxval(AT_MINSIGSTKSZ) as usize }
+        unsafe { libc_getauxval(c::AT_MINSIGSTKSZ) as usize }
     } else {
         0
     }

src/backend/linux_raw/param/libc_auxv.rs

@@ -39,6 +39,7 @@ const AT_HWCAP2: c::c_ulong = 26;
 const AT_SECURE: c::c_ulong = 23;
 const AT_EXECFN: c::c_ulong = 31;
 const AT_SYSINFO_EHDR: c::c_ulong = 33;
+const AT_MINSIGSTKSZ: c::c_ulong = 51;
 
 // Declare `sysconf` ourselves so that we don't depend on all of libc just for
 // this.
@@ -64,6 +65,7 @@ fn test_abi() {
     const_assert_eq!(self::AT_EXECFN, ::libc::AT_EXECFN);
     const_assert_eq!(self::AT_SECURE, ::libc::AT_SECURE);
     const_assert_eq!(self::AT_SYSINFO_EHDR, ::libc::AT_SYSINFO_EHDR);
+    const_assert_eq!(self::AT_MINSIGSTKSZ, ::libc::AT_MINSIGSTKSZ);
     #[cfg(feature = "runtime")]
     const_assert_eq!(self::AT_PHDR, ::libc::AT_PHDR);
     #[cfg(feature = "runtime")]
@@ -111,9 +113,6 @@ pub(crate) fn linux_hwcap() -> (usize, usize) {
 #[cfg(feature = "param")]
 #[inline]
 pub(crate) fn linux_minsigstksz() -> usize {
-    // FIXME: reuse const from libc when available?
-    const AT_MINSIGSTKSZ: c::c_ulong = 51;
-
     #[cfg(not(feature = "runtime"))]
     if let Some(libc_getauxval) = getauxval.get() {
         unsafe { libc_getauxval(AT_MINSIGSTKSZ) as usize }

tests/param/auxv.rs

@@ -49,11 +49,9 @@ fn test_linux_minsigstksz() {
     weak!(fn getauxval(libc::c_ulong) -> libc::c_ulong);
 
     if let Some(libc_getauxval) = getauxval.get() {
-        // FIXME: reuse const from libc when available?
-        const AT_MINSIGSTKSZ: libc::c_ulong = 51;
         assert_eq!(
             linux_minsigstksz(),
-            unsafe { libc_getauxval(AT_MINSIGSTKSZ) } as usize
+            unsafe { libc_getauxval(libc::AT_MINSIGSTKSZ) } as usize
         );
     }
 }