diff --git a/configure.ac b/configure.ac
index 46036113b8..f6d983fda8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -262,6 +262,7 @@ AC_CHECK_FUNCS([setresuid setreuid lchown])
 # Nice to have, but not essential.
 AC_CHECK_FUNCS([strsignal])
 AC_CHECK_FUNCS([posix_fallocate])
+AC_CHECK_FUNCS([fdatasync])
 
 
 # This is needed if ATerm or bzip2 are static libraries,
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 837382433a..90132da733 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -12,6 +12,10 @@
 
 #include <cstdio>
 
+#ifndef HAVE_FDATASYNC
+#define fdatasync fsync
+#endif
+
 
 namespace nix {