fix compilation errors
diff --git a/src/core/iomgr/unix_sockets_posix.c b/src/core/iomgr/unix_sockets_posix.c
index 035b55f..8ff474c 100644
--- a/src/core/iomgr/unix_sockets_posix.c
+++ b/src/core/iomgr/unix_sockets_posix.c
@@ -35,6 +35,7 @@
 
 #ifdef GPR_HAVE_UNIX_SOCKET
 
+#include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/un.h>