diff -u openbsd-compat/bsd-statvfs.c openbsd-compat/bsd-statvfs.c
--- openbsd-compat/bsd-statvfs.c	2017-10-02 20:34:26.000000000 +0000
+++ openbsd-compat/bsd-statvfs.c	2018-01-04 23:28:17.000000000 +0000
@@ -25,6 +25,8 @@
 
 #include <errno.h>
 
+#if ((!defined(HAVE_STATVFS) && defined(HAVE_STATFS)) || \
+     (!defined(HAVE_FSTATVFS) && defined(HAVE_FSTATFS)))
 static void
 copy_statfs_to_statvfs(struct statvfs *to, struct statfs *from)
 {
@@ -40,6 +42,7 @@
 	to->f_flag = from->f_flags;
 	to->f_namemax = MNAMELEN;
 }
+#endif
 
 # ifndef HAVE_STATVFS
 int statvfs(const char *path, struct statvfs *buf)
diff -u openbsd-compat/bsd-statvfs.h openbsd-compat/bsd-statvfs.h
--- openbsd-compat/bsd-statvfs.h	2017-10-02 20:34:26.000000000 +0000
+++ openbsd-compat/bsd-statvfs.h	2018-01-05 11:28:03.000000000 +0000
@@ -42,6 +42,8 @@
 #endif
 
 	/* as defined in IEEE Std 1003.1, 2004 Edition */
+#if ((!defined(HAVE_STATVFS) && defined(HAVE_STATFS)) || \ 
+     (!defined(HAVE_FSTATVFS) && defined(HAVE_FSTATFS))) 
 struct statvfs {
 	unsigned long f_bsize;	/* File system block size. */
 	unsigned long f_frsize;	/* Fundamental file system block size. */
@@ -59,6 +61,7 @@
 	unsigned long f_namemax;/*  Maximum filename length. */
 };
 #endif
+#endif
 
 #ifndef HAVE_STATVFS
 int statvfs(const char *, struct statvfs *);