Fix the missing tests in the Linux build.

CMakeLists.txt

@@ -30,6 +30,7 @@ SET(PICOQUIC_LIBRARY_FILES
 
 SET(PICOQUIC_TEST_LIBRARY_FILES
     picoquictest/ack_of_ack_test.c
+    picoquictest/cleartext_aead_test.c
     picoquictest/cnx_creation_test.c
     picoquictest/float16test.c
     picoquictest/fnv1atest.c

picoquictest/cleartext_aead_test.c

@@ -19,6 +19,7 @@
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+#include <string.h>
 #include "../picoquic/picoquic_internal.h"
 #include "../picoquic/tls_api.h"
 
@@ -172,4 +173,5 @@ int cleartext_aead_test()
     }
 
     return ret;
-}
\ No newline at end of file
+}
+