Build fails with LTO

[eli-schwartz]

Build fails with LTO

[eli-schwartz]

It also fails with strict-aliasing violations, specifically in the testsuite.

x86_64-pc-linux-gnu-g++ -DHAVE_CONFIG_H -I. -I..  -I../GNU -I.. -I../tests  -I/usr/include/libxml2 -I/usr/include/tirpc   --std=c++14   -g -O2  -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -fstack-clash-protection -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -std=c++14 -c -o ddsT.o ddsT.cc
ddsT.cc: In member function ‘void ddsT::ddsT_test()’:
ddsT.cc:239:44: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  239 |                 vs_iter &vsi = (vs_iter &) vsc;
      |                                            ^~~
ddsT.cc:274:44: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  274 |                 vs_iter &vsi = (vs_iter &) vsc;
      |                                            ^~~
ddsT.cc:302:44: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  302 |                 vs_iter &vsi = (vs_iter &) vsc;
      |                                            ^~~
ddsT.cc:303:45: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  303 |                 vs_iter &vsi2 = (vs_iter &) vsc2;
      |                                             ^~~~
cc1plus: some warnings being treated as errors

Originally reported downstream: https://bugs.gentoo.org/878895

[jgallagher59701]

OK, I'll look into this. Thanks.