diff --git a/lib/libc/sys/close.c b/lib/libc/sys/close.c
index 02e74c633001..f7b36f85ddd5 100644
--- a/lib/libc/sys/close.c
+++ b/lib/libc/sys/close.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/fcntl.h>
+#include <unistd.h>
 #include "libc_private.h"
 
 __weak_reference(__sys_close, __close);
diff --git a/lib/libc/sys/fsync.c b/lib/libc/sys/fsync.c
index 3fff428f1ab7..5f1512932baa 100644
--- a/lib/libc/sys/fsync.c
+++ b/lib/libc/sys/fsync.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/fcntl.h>
+#include <unistd.h>
 #include "libc_private.h"
 
 __weak_reference(__sys_fsync, __fsync);
diff --git a/lib/libc/sys/msync.c b/lib/libc/sys/msync.c
index 3c6879f04c64..d86cc0462dd8 100644
--- a/lib/libc/sys/msync.c
+++ b/lib/libc/sys/msync.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/fcntl.h>
+#include <sys/mman.h>
 #include "libc_private.h"
 
 __weak_reference(__sys_msync, __msync);
diff --git a/lib/libc/sys/readv.c b/lib/libc/sys/readv.c
index 8c82040367cc..567292750da0 100644
--- a/lib/libc/sys/readv.c
+++ b/lib/libc/sys/readv.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/syscall.h>
+#include <sys/uio.h>
 #include <unistd.h>
 #include "libc_private.h"
 
diff --git a/lib/libc/sys/writev.c b/lib/libc/sys/writev.c
index 6be74b3c31d1..20b10053dc59 100644
--- a/lib/libc/sys/writev.c
+++ b/lib/libc/sys/writev.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/syscall.h>
+#include <sys/uio.h>
 #include <unistd.h>
 #include "libc_private.h"