GCC 4.8 LTO Crashes

[ax3l]

Issue description

Several places on the internet see build issues of pybind11 with GCC 4.8, probably in a linker bug during LTO:

• https://stackoverflow.com/questions/47819210/pybind11-lto-wrapper-failed
• py-pybind11 build fails (lto-wrapper failed) spack/spack#7618

lto1: internal compiler error: in build_abbrev_table, at dwarf2out.c:7478

Have you seen this with pybind11 before?

Is there a way to externally pass NO_EXTRAS in calls to pybind11_add_module via generic pybind11 CMake options? This would allow users to build pybind11 projects on GCC 4.8 without triggering the bug and without re-writing CMake files of packages (e.g. packaging solutions such as conda or spack).

Maybe this is also just a mismatch between dependencies in those reports in the compile chain?

Reproducible example code

I saw this recently on Travis-CI but can't reproduce it in docker containers (yet).

Works on Ubuntu Trusty:

$ docker pull ubuntu:14.04
$ docker run -it ubuntu:14.04

> apt-get update
> apt-get install -y python-dev python-pip git cmake g++ make
> pip install -U pytest

> git clone https://github.com/pybind/pybind11.git
# cd pybind11 && git checkout v2.2.2 && cd ..
> mkdir build
> cd build

> cmake ../pybind11
# gcc 4.8.4
> make
# ...

Surprisingly works on Centos 7:

$ docker pull centos:7
$ docker run -it centos:7

> yum -y update
> yum install -y epel-release
> yum install -y python-devel python-pip git cmake gcc gcc-c++ make
> pip install -U pytest
> git clone https://github.com/pybind/pybind11.git
> mkdir build
> cd build

> cmake ../pybind11
# gcc 4.8.5
> make
# ...

[henryiii]

I have an idea, actually, as a follow up to #2338.