diff --git a/libc-test/build.rs b/libc-test/build.rs
index ee68b64fd0f7e..f1b1bd470ddb1 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -82,6 +82,7 @@ fn main() {
 
     if android {
         cfg.header("arpa/inet.h");
+        cfg.header("time64.h");
     } else if !windows {
         cfg.header("glob.h");
         cfg.header("ifaddrs.h");
@@ -232,6 +233,10 @@ fn main() {
             "dlerror" if android => true, // const-ness is added
             "dladdr" if musl => true, // const-ness only added recently
 
+            // OSX has 'struct tm *const' which we can't actually represent in
+            // Rust, but is close enough to *mut
+            "timegm" if apple => true,
+
             _ => false,
         }
     });
diff --git a/src/unix/bsd/mod.rs b/src/unix/bsd/mod.rs
index 62444f6215180..76f1ee766aeb2 100644
--- a/src/unix/bsd/mod.rs
+++ b/src/unix/bsd/mod.rs
@@ -66,6 +66,20 @@ s! {
     pub struct fd_set {
         fds_bits: [i32; FD_SETSIZE / 32],
     }
+
+    pub struct tm {
+        pub tm_sec: ::c_int,
+        pub tm_min: ::c_int,
+        pub tm_hour: ::c_int,
+        pub tm_mday: ::c_int,
+        pub tm_mon: ::c_int,
+        pub tm_year: ::c_int,
+        pub tm_wday: ::c_int,
+        pub tm_yday: ::c_int,
+        pub tm_isdst: ::c_int,
+        pub tm_gmtoff: ::c_long,
+        pub tm_zone: *mut ::c_char,
+    }
 }
 
 pub const FIOCLEX: ::c_ulong = 0x20006601;
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 636b5d3c98ae7..f1e4ffa607a28 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -450,6 +450,12 @@ extern {
                        res: *mut *mut addrinfo) -> ::c_int;
     pub fn freeaddrinfo(res: *mut addrinfo);
     pub fn gai_strerror(errcode: ::c_int) -> *const ::c_char;
+
+    pub fn gmtime_r(time_p: *const time_t, result: *mut tm) -> *mut tm;
+    pub fn localtime_r(time_p: *const time_t, result: *mut tm) -> *mut tm;
+    #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
+               link_name = "mktime$UNIX2003")]
+    pub fn mktime(tm: *mut tm) -> time_t;
 }
 
 // TODO: get rid of this #[cfg(not(...))]
@@ -551,6 +557,7 @@ extern {
                   offset: ::off_t,
                   whence: ::c_int) -> ::c_int;
     pub fn ftello(stream: *mut ::FILE) -> ::off_t;
+    pub fn timegm(tm: *mut ::tm) -> time_t;
 }
 
 cfg_if! {
diff --git a/src/unix/notbsd/android/mod.rs b/src/unix/notbsd/android/mod.rs
index 37678f4ebbb05..2cca05e457e1c 100644
--- a/src/unix/notbsd/android/mod.rs
+++ b/src/unix/notbsd/android/mod.rs
@@ -19,6 +19,7 @@ pub type socklen_t = i32;
 pub type pthread_t = c_long;
 pub type pthread_mutexattr_t = ::c_long;
 pub type sigset_t = c_ulong;
+pub type time64_t = i64;
 
 s! {
     pub struct stat {
@@ -225,6 +226,7 @@ extern {
                        serv: *mut ::c_char,
                        sevlen: ::size_t,
                        flags: ::c_int) -> ::c_int;
+    pub fn timegm64(tm: *const ::tm) -> time64_t;
 }
 
 cfg_if! {
diff --git a/src/unix/notbsd/mod.rs b/src/unix/notbsd/mod.rs
index ed84bef24780c..cb4d0c0a308de 100644
--- a/src/unix/notbsd/mod.rs
+++ b/src/unix/notbsd/mod.rs
@@ -72,6 +72,20 @@ s! {
     pub struct fd_set {
         fds_bits: [::c_ulong; FD_SETSIZE / ULONG_SIZE],
     }
+
+    pub struct tm {
+        pub tm_sec: ::c_int,
+        pub tm_min: ::c_int,
+        pub tm_hour: ::c_int,
+        pub tm_mday: ::c_int,
+        pub tm_mon: ::c_int,
+        pub tm_year: ::c_int,
+        pub tm_wday: ::c_int,
+        pub tm_yday: ::c_int,
+        pub tm_isdst: ::c_int,
+        pub tm_gmtoff: ::c_long,
+        pub tm_zone: *const ::c_char,
+    }
 }
 
 // intentionally not public, only used for fd_set