diff --git a/libc-test/build.rs b/libc-test/build.rs
index b8e8ac85c073dc57540a3701284ae3f4f7ed9703..4be4dde373bf33fe8f8dbb6b4061b3ba3e0e0c86 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -150,6 +150,7 @@ fn test_apple(target: &str) {
         "sys/sysctl.h",
         "sys/time.h",
         "sys/times.h",
+        "sys/timex.h",
         "sys/types.h",
         "sys/uio.h",
         "sys/un.h",
@@ -819,6 +820,7 @@ fn test_netbsd(target: &str) {
         "sys/sysctl.h",
         "sys/time.h",
         "sys/times.h",
+        "sys/timex.h",
         "sys/uio.h",
         "sys/un.h",
         "sys/utsname.h",
@@ -1569,6 +1571,7 @@ fn test_freebsd(target: &str) {
                 "sys/sysctl.h",
                 "sys/time.h",
                 "sys/times.h",
+                "sys/timex.h",
                 "sys/types.h",
                 "sys/uio.h",
                 "sys/un.h",
@@ -2183,6 +2186,7 @@ fn test_linux(target: &str) {
                "sys/time.h",
                "sys/timerfd.h",
                "sys/times.h",
+               "sys/timex.h",
                "sys/types.h",
                "sys/uio.h",
                "sys/un.h",