diff --git a/build.rs b/build.rs
index 76ca0961e4782..f355447a672c6 100644
--- a/build.rs
+++ b/build.rs
@@ -16,9 +16,15 @@ fn main() {
     }
 
     if env::var("LIBC_CI").is_ok() {
+        if let Some(11) = which_freebsd() {
+            println!("cargo:rustc-cfg=freebsd11");
+        }
         if let Some(12) = which_freebsd() {
             println!("cargo:rustc-cfg=freebsd12");
         }
+        if let Some(13) = which_freebsd() {
+            println!("cargo:rustc-cfg=freebsd13");
+        }
     }
 
     // Rust >= 1.15 supports private module use:
@@ -100,6 +106,7 @@ fn which_freebsd() -> Option<i32> {
     match &stdout {
         s if s.starts_with("11") => Some(11),
         s if s.starts_with("12") => Some(12),
+        s if s.starts_with("13") => Some(13),
         _ => None,
     }
 }
diff --git a/libc-test/build.rs b/libc-test/build.rs
index 7eafc086c694d..146beb073442b 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -1455,10 +1455,12 @@ fn test_freebsd(target: &str) {
 
     let freebsd_ver = which_freebsd();
 
-    if let Some(12) = freebsd_ver {
-        // If the host is FreeBSD 12, run FreeBSD 12 tests
-        cfg.cfg("freebsd12", None);
-    }
+    match freebsd_ver {
+        Some(11) => cfg.cfg("freebsd11", None),
+        Some(12) => cfg.cfg("freebsd12", None),
+        Some(13) => cfg.cfg("freebsd13", None),
+        _ => &mut cfg,
+    };
 
     // Required for `getline`:
     cfg.define("_WITH_GETLINE", None);
@@ -1586,7 +1588,7 @@ fn test_freebsd(target: &str) {
             | "IP_RECVORIGDSTADDR"
             | "IPV6_ORIGDSTADDR"
             | "IPV6_RECVORIGDSTADDR"
-                if Some(12) != freebsd_ver =>
+                if Some(11) == freebsd_ver =>
             {
                 true
             }
@@ -2472,6 +2474,7 @@ fn which_freebsd() -> Option<i32> {
     match &stdout {
         s if s.starts_with("11") => Some(11),
         s if s.starts_with("12") => Some(12),
+        s if s.starts_with("13") => Some(13),
         _ => None,
     }
 }
diff --git a/src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs b/src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs
index 7d7dc2c1d4902..b71b284e42554 100644
--- a/src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs
@@ -189,6 +189,8 @@ cfg_if! {
     }
 }
 
+pub const ELAST: ::c_int = 96;
+
 extern {
     // Return type ::c_int was removed in FreeBSD 12
     pub fn setgrent() -> ::c_int;
diff --git a/src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs b/src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs
index ab1b8d98357b3..464744d140da4 100644
--- a/src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/freebsd12/mod.rs
@@ -190,6 +190,15 @@ cfg_if! {
     }
 }
 
+cfg_if! {
+    if #[cfg(not(freebsd13))] {
+        pub const ELAST: ::c_int = 96;
+    } else {
+        pub const EINTEGRITY: ::c_int = 97;
+        pub const ELAST: ::c_int = 97;
+    }
+}
+
 extern {
     pub fn setgrent();
     pub fn mprotect(addr: *mut ::c_void, len: ::size_t, prot: ::c_int)
diff --git a/src/unix/bsd/freebsdlike/freebsd/mod.rs b/src/unix/bsd/freebsdlike/freebsd/mod.rs
index 9f11c202bb4ea..c178b91b9408e 100644
--- a/src/unix/bsd/freebsdlike/freebsd/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/mod.rs
@@ -333,7 +333,6 @@ pub const ENOTCAPABLE: ::c_int = 93;
 pub const ECAPMODE: ::c_int = 94;
 pub const ENOTRECOVERABLE: ::c_int = 95;
 pub const EOWNERDEAD: ::c_int = 96;
-pub const ELAST: ::c_int = 96;
 pub const RLIMIT_NPTS: ::c_int = 11;
 pub const RLIMIT_SWAP: ::c_int = 12;
 pub const RLIMIT_KQUEUES: ::c_int = 13;
@@ -1332,6 +1331,9 @@ cfg_if! {
     if #[cfg(freebsd12)] {
         mod freebsd12;
         pub use self::freebsd12::*;
+    } else if #[cfg(freebsd13)] {
+        mod freebsd12;
+        pub use self::freebsd12::*;
     } else {
         mod freebsd11;
         pub use self::freebsd11::*;
diff --git a/src/unix/bsd/freebsdlike/mod.rs b/src/unix/bsd/freebsdlike/mod.rs
index ce5452062ce3d..f937d772a9a44 100644
--- a/src/unix/bsd/freebsdlike/mod.rs
+++ b/src/unix/bsd/freebsdlike/mod.rs
@@ -1152,7 +1152,7 @@ extern {
     pub fn getutxline(ut: *const utmpx) -> *mut utmpx;
     pub fn initgroups(name: *const ::c_char, basegid: ::gid_t) -> ::c_int;
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "kevent@FBSD_1.0"
     )]
     pub fn kevent(kq: ::c_int,
@@ -1171,7 +1171,7 @@ extern {
     pub fn mkfifoat(dirfd: ::c_int, pathname: *const ::c_char,
                     mode: ::mode_t) -> ::c_int;
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "mknodat@FBSD_1.1"
     )]
     pub fn mknodat(dirfd: ::c_int, pathname: *const ::c_char,
diff --git a/src/unix/bsd/mod.rs b/src/unix/bsd/mod.rs
index 77f82b182bb57..ee644114a4867 100644
--- a/src/unix/bsd/mod.rs
+++ b/src/unix/bsd/mod.rs
@@ -536,7 +536,7 @@ extern {
     #[cfg_attr(target_os = "macos", link_name = "glob$INODE64")]
     #[cfg_attr(target_os = "netbsd", link_name = "__glob30")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "glob@FBSD_1.0"
     )]
     pub fn glob(pattern: *const ::c_char,
@@ -546,7 +546,7 @@ extern {
                 pglob: *mut ::glob_t) -> ::c_int;
     #[cfg_attr(target_os = "netbsd", link_name = "__globfree30")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "globfree@FBSD_1.0"
     )]
     pub fn globfree(pglob: *mut ::glob_t);
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 65cf7ecf5c05d..721d241164a1d 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -567,7 +567,7 @@ extern {
     #[cfg_attr(target_os = "macos", link_name = "fstat$INODE64")]
     #[cfg_attr(target_os = "netbsd", link_name = "__fstat50")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "fstat@FBSD_1.0"
     )]
     pub fn fstat(fildes: ::c_int, buf: *mut stat) -> ::c_int;
@@ -577,7 +577,7 @@ extern {
     #[cfg_attr(target_os = "macos", link_name = "stat$INODE64")]
     #[cfg_attr(target_os = "netbsd", link_name = "__stat50")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "stat@FBSD_1.0"
     )]
     pub fn stat(path: *const c_char, buf: *mut stat) -> ::c_int;
@@ -608,7 +608,7 @@ extern {
     #[cfg_attr(target_os = "macos", link_name = "readdir$INODE64")]
     #[cfg_attr(target_os = "netbsd", link_name = "__readdir30")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "readdir@FBSD_1.0"
     )]
     pub fn readdir(dirp: *mut ::DIR) -> *mut ::dirent;
@@ -631,7 +631,7 @@ extern {
                     flags: ::c_int) -> ::c_int;
     #[cfg_attr(target_os = "macos", link_name = "fstatat$INODE64")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "fstatat@FBSD_1.1"
     )]
     pub fn fstatat(dirfd: ::c_int, pathname: *const ::c_char,
@@ -786,7 +786,7 @@ extern {
     #[cfg_attr(target_os = "macos", link_name = "lstat$INODE64")]
     #[cfg_attr(target_os = "netbsd", link_name = "__lstat50")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "lstat@FBSD_1.0"
     )]
     pub fn lstat(path: *const c_char, buf: *mut stat) -> ::c_int;
@@ -962,7 +962,7 @@ extern {
 
     #[cfg_attr(target_os = "netbsd", link_name = "__mknod50")]
     #[cfg_attr(
-        all(target_os = "freebsd", not(freebsd12)),
+        all(target_os = "freebsd", freebsd11),
         link_name = "mknod@FBSD_1.0"
     )]
     pub fn mknod(pathname: *const ::c_char, mode: ::mode_t,
@@ -1126,7 +1126,7 @@ cfg_if! {
             #[cfg_attr(target_os = "macos", link_name = "readdir_r$INODE64")]
             #[cfg_attr(target_os = "netbsd", link_name = "__readdir_r30")]
             #[cfg_attr(
-                all(target_os = "freebsd", not(freebsd12)),
+                all(target_os = "freebsd", freebsd11),
                 link_name = "readdir_r@FBSD_1.0"
             )]
             /// The 64-bit libc on Solaris and illumos only has readdir_r.  If a