add missing #include

diff --git a/riscv/sim.cc b/riscv/sim.cc
index 6d98d8e122e8b776f4e6f58865f7229a91ef34eb..1cac94f25babe5c4a0ff6f7df0a1ebd2f6b7d802 100644 (file)
--- a/riscv/sim.cc
+++ b/riscv/sim.cc
@@ -5,6 +5,7 @@
 #include <iostream>
 #include <climits>
 #include <assert.h>
+#include <unistd.h>
 
 #ifdef __linux__
 # define mmap mmap64