diff --git a/configure.ac b/configure.ac
index 2240c725c..9b05c30f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1674,7 +1674,6 @@ AC_CHECK_FUNCS([ \
 	pstat \
 	readpassphrase \
 	reallocarray \
-	realpath \
 	recvmsg \
 	rresvport_af \
 	sendmsg \
@@ -1891,6 +1890,32 @@ AC_CHECK_FUNCS([setresgid], [
 	)
 ])
 
+AC_CHECK_FUNCS([realpath], [
+	dnl the sftp v3 spec says SSH_FXP_REALPATH will "canonicalize any given
+	dnl path name", however some implementations of realpath (and some
+	dnl versions of the POSIX spec) do not work on non-existent files,
+	dnl so we use the OpenBSD implementation on those platforms.
+	AC_MSG_CHECKING([if realpath works with non-existent files])
+	AC_RUN_IFELSE(
+		[AC_LANG_PROGRAM([[
+#include <limits.h>
+#include <stdlib.h>
+#include <errno.h>
+		]], [[
+		char buf[PATH_MAX];
+		if (realpath("/opensshnonexistentfilename1234", buf) == NULL)
+			if (errno == ENOENT)
+				exit(1);
+		exit(0);
+		]])],
+		[AC_MSG_RESULT([yes])],
+		[AC_DEFINE([BROKEN_REALPATH], [1],
+			[realpath does not work with nonexistent files])
+		 AC_MSG_RESULT([no])],
+		[AC_MSG_WARN([cross compiling: assuming working])]
+	)
+])
+
 dnl    Checks for time functions
 AC_CHECK_FUNCS([gettimeofday time])
 dnl    Checks for utmp functions
diff --git a/openbsd-compat/openbsd-compat.h b/openbsd-compat/openbsd-compat.h
index cb59ccd57..1ff7114ef 100644
--- a/openbsd-compat/openbsd-compat.h
+++ b/openbsd-compat/openbsd-compat.h
@@ -70,8 +70,16 @@ void *reallocarray(void *, size_t, size_t);
 #endif
 
 #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH)
+/*
+ * glibc's FORTIFY_SOURCE can redefine this and prevent us picking up the
+ * compat version.
+ */
+# ifdef BROKEN_REALPATH
+#  define realpath(x, y) _ssh_compat_realpath(x, y)
+# endif
+
 char *realpath(const char *path, char *resolved);
-#endif 
+#endif
 
 #ifndef HAVE_RRESVPORT_AF
 int rresvport_af(int *alport, sa_family_t af);