Disable LTO.

nbdkit.spec

@@ -45,7 +45,7 @@ ExclusiveArch:  x86_64
 
 Name:           nbdkit
 Version:        1.21.20
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        NBD server
 
 License:        BSD
@@ -667,6 +667,10 @@ autoreconf -i
 
 
 %build
+# Disable LTO, it's unreliable.  See for example:
+# https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/ULGH5JYL7MHKDKTINJLOEN2QG6LOHWH7/
+%define _lto_cflags %{nil}
+
 # Golang bindings are not enabled in the Fedora build since they don't
 # need to be.  Most people would use them by copying the upstream
 # package into their vendor/ directory.
@@ -1071,8 +1075,9 @@ export LIBGUESTFS_TRACE=1
 
 
 %changelog
-* Fri Jul 31 2020 Richard W.M. Jones <rjones@redhat.com> - 1.21.20-3
+* Fri Jul 31 2020 Richard W.M. Jones <rjones@redhat.com> - 1.21.20-4
 - Add upstream patch to try to track down test failure in Koji.
+- Disable LTO.
 
 * Tue Jul 28 2020 Fedora Release Engineering <releng@fedoraproject.org> - 1.21.20-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild