Add missing includes.

Change-Id: Ibf549266a19a67eb9158d341a69dddfb654be669
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index 7406b35..c6d8494 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -29,6 +29,7 @@
 #include <pthread.h>
 
 #include <errno.h>
+#include <string.h>
 #include <sys/mman.h>
 #include <unistd.h>