Redisable constants for L4Re

These constants were disabled for uclibc (and therefore implicitly
disabled for L4Re). Now that they are not disabled for uclibc anymore,
explicitly disable them for L4Re.

Author: farao

src/unix/linux_like/linux_l4re_shared.rs

@@ -795,6 +795,7 @@ pub const EM_M32R: u16 = 88;
 pub const EM_MN10300: u16 = 89;
 pub const EM_MN10200: u16 = 90;
 pub const EM_PJ: u16 = 91;
+#[cfg(not(target_os = "l4re"))]
 pub const EM_OPENRISC: u16 = 92;
 #[cfg(target_env = "uclibc")]
 pub const EM_OR1K: u16 = 92;
@@ -875,6 +876,7 @@ pub const AT_EXECFN: c_ulong = 31;
 // defined in arch/<arch>/include/uapi/asm/auxvec.h but has the same value
 // wherever it is defined.
 pub const AT_SYSINFO_EHDR: c_ulong = 33;
+#[cfg(not(target_os = "l4re"))]
 pub const AT_MINSIGSTKSZ: c_ulong = 51;
 
 pub const GLOB_ERR: c_int = 1 << 0;