diff -uNr sdcv-0.5.2/src/mapfile.hpp sdcv-0.5.2.mod/src/mapfile.hpp
--- sdcv-0.5.2/src/mapfile.hpp	2017-08-16 10:14:23.000000000 +0300
+++ sdcv-0.5.2.mod/src/mapfile.hpp	2019-01-20 17:11:14.779052646 +0200
@@ -6,6 +6,7 @@
 
 #ifdef HAVE_MMAP
 #include <fcntl.h>
+#include <unistd.h>
 #include <sys/mman.h>
 #include <sys/types.h>
 #endif