diff --git a/include/libunwind-x86_64.h b/include/libunwind-x86_64.h
index e3373516..53789cc3 100644
--- a/include/libunwind-x86_64.h
+++ b/include/libunwind-x86_64.h
@@ -32,6 +32,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 extern "C" {
 #endif
 
+#include <sys/types.h>
 #include <inttypes.h>
 #include <ucontext.h>