Include a needed file
diff --git a/src/bc/program.c b/src/bc/program.c
index 38e628d..771e033 100644
--- a/src/bc/program.c
+++ b/src/bc/program.c
@@ -25,7 +25,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include <arbprec/arbprec.h>
+#include <unistd.h>
 
 #include <io.h>
 #include <program.h>