Created attachment 810999 [details]
petsc_gnu_openmpi3_hpc_standard_x86_64_201907190841.log

LTO: petsc:gnu-openmpi3-hpc build hang

as reported in 
https://build.opensuse.org/project/show/openSUSE:Factory:Staging:adi:26

the first log extract
===
[  120s] TESTING: checkMPICHorOpenMPI from
config.packages.MPI(/home/abuild/rpmbuild/BUILD/petsc-3.8.3/config/BuildSystem/config/packages/MPI.py:431)
[  120s] TESTING: checkSharedLibrary from
config.packages.MPI(/home/abuild/rpmbuild/BUILD/petsc-3.8.3/config/BuildSystem/config/packages/MPI.py:128)
[ 5530s] TESTING: configureMPIEXEC from
config.packages.MPI(/home/abuild/rpmbuild/BUILD/petsc-3.8.3/config/BuildSystem/config/packages/MPI.py:141)qemu-system-x86_64:
terminating on signal 15 from pid 12869 (<unknown process>)
===

If I am removing lto with "%define _lto_cflags %{nil}"
then no more failure as per second attached log.