[Fuzzer] Add a missing header in Fuchsia implementation

This is needed for fd_set.

Differential Revision: https://reviews.llvm.org/D45852

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@330383 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerUtilFuchsia.cpp b/FuzzerUtilFuchsia.cpp
index 73974e5..f98c68a 100644
--- a/FuzzerUtilFuchsia.cpp
+++ b/FuzzerUtilFuchsia.cpp
@@ -20,6 +20,7 @@
 #include <fcntl.h>
 #include <launchpad/launchpad.h>
 #include <string>
+#include <sys/select.h>
 #include <thread>
 #include <unistd.h>
 #include <zircon/errors.h>