diff --git a/t/t_adler.c b/t/t_adler.c
index 3642d95..2b78103 100644
--- a/t/t_adler.c
+++ b/t/t_adler.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_aes.c b/t/t_aes.c
index 876f0a7..2deed0c 100644
--- a/t/t_aes.c
+++ b/t/t_aes.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_ctype.c b/t/t_ctype.c
index 2b6f1c8..99b9cd7 100644
--- a/t/t_ctype.c
+++ b/t/t_ctype.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_endian.c b/t/t_endian.c
index c6896b1..61f9082 100644
--- a/t/t_endian.c
+++ b/t/t_endian.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_fletcher.c b/t/t_fletcher.c
index b3b2de5..f133749 100644
--- a/t/t_fletcher.c
+++ b/t/t_fletcher.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_hmac_sha1.c b/t/t_hmac_sha1.c
index fe8d2d2..30cffc5 100644
--- a/t/t_hmac_sha1.c
+++ b/t/t_hmac_sha1.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/t/t_hmac_sha224.c b/t/t_hmac_sha224.c
index 7640c3e..5f2d9fb 100644
--- a/t/t_hmac_sha224.c
+++ b/t/t_hmac_sha224.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/t/t_hmac_sha256.c b/t/t_hmac_sha256.c
index 7f72758..9f56976 100644
--- a/t/t_hmac_sha256.c
+++ b/t/t_hmac_sha256.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/t/t_hmac_sha384.c b/t/t_hmac_sha384.c
index 3d70eb9..8a60627 100644
--- a/t/t_hmac_sha384.c
+++ b/t/t_hmac_sha384.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/t/t_hmac_sha512.c b/t/t_hmac_sha512.c
index f9514b3..9f1ad51 100644
--- a/t/t_hmac_sha512.c
+++ b/t/t_hmac_sha512.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/t/t_md2.c b/t/t_md2.c
index c55b9e3..dfa7336 100644
--- a/t/t_md2.c
+++ b/t/t_md2.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_md4.c b/t/t_md4.c
index c001361..eb8995d 100644
--- a/t/t_md4.c
+++ b/t/t_md4.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_md5.c b/t/t_md5.c
index e926e51..c4252c7 100644
--- a/t/t_md5.c
+++ b/t/t_md5.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_memset_s.c b/t/t_memset_s.c
index ed856ce..da1639c 100644
--- a/t/t_memset_s.c
+++ b/t/t_memset_s.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <errno.h>
 #include <stdint.h>
 #include <string.h>
diff --git a/t/t_mpi.c b/t/t_mpi.c
index aedb6e2..61480d0 100644
--- a/t/t_mpi.c
+++ b/t/t_mpi.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <assert.h>
 #include <stdint.h>
 #include <string.h>
diff --git a/t/t_murmur3_32.c b/t/t_murmur3_32.c
index fedd000..e51d986 100644
--- a/t/t_murmur3_32.c
+++ b/t/t_murmur3_32.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/t/t_pearson.c b/t/t_pearson.c
index ee6a979..8aea2f7 100644
--- a/t/t_pearson.c
+++ b/t/t_pearson.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/t/t_rc4.c b/t/t_rc4.c
index aee64a2..c41abba 100644
--- a/t/t_rc4.c
+++ b/t/t_rc4.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_rfc3986.c b/t/t_rfc3986.c
index e887a5a..f401862 100644
--- a/t/t_rfc3986.c
+++ b/t/t_rfc3986.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
diff --git a/t/t_rfc4648.c b/t/t_rfc4648.c
index e5bde13..d6d9903 100644
--- a/t/t_rfc4648.c
+++ b/t/t_rfc4648.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
diff --git a/t/t_sha1.c b/t/t_sha1.c
index 7dbc8ae..fd121c4 100644
--- a/t/t_sha1.c
+++ b/t/t_sha1.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_sha224.c b/t/t_sha224.c
index 3134917..ebe195f 100644
--- a/t/t_sha224.c
+++ b/t/t_sha224.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_sha256.c b/t/t_sha256.c
index a00f9fa..767ae40 100644
--- a/t/t_sha256.c
+++ b/t/t_sha256.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_sha384.c b/t/t_sha384.c
index a0c9cf8..c6ac194 100644
--- a/t/t_sha384.c
+++ b/t/t_sha384.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_sha512.c b/t/t_sha512.c
index 7fd27a7..1c25c82 100644
--- a/t/t_sha512.c
+++ b/t/t_sha512.c
@@ -30,6 +30,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/t/t_strlcat.c b/t/t_strlcat.c
index 12734ca..c040f74 100644
--- a/t/t_strlcat.c
+++ b/t/t_strlcat.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/t/t_strlcmp.c b/t/t_strlcmp.c
index a5d1797..5a11b46 100644
--- a/t/t_strlcmp.c
+++ b/t/t_strlcmp.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/t/t_strlcpy.c b/t/t_strlcpy.c
index f1f9c15..ffa9c20 100644
--- a/t/t_strlcpy.c
+++ b/t/t_strlcpy.c
@@ -29,6 +29,8 @@
 
 #include "cryb/impl.h"
 
+#include <sys/types.h>
+
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>