clblas is not buildable

[Shimuuar]

Issue description

clblas is not buildable

Steps to reproduce

1. nix-shell -p clblas which will fail with obscure compile error

Build fails because of some incompatibility of gtest but if one uses vendored version build succeed without any problem. To do so one need to remove cmake's flag -DUSE_SYSTEM_GTEST=ON from derivations. So if one overrides clblas like this it builds fine:

    clblas = self.lib.overrideDerivation super.clblas (oldAttrs: {
      cmakeFlags = [];
    });

I only tested it on 18.09 but according to hydra 19.03 suffers from same problem

Technical details

Please run nix-shell -p nix-info --run "nix-info -m" and paste the
results.

 - system: `"x86_64-linux"`
 - host os: `Linux 4.14.108, NixOS, 18.09.2394.2d656a97297 (Jellyfish)`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.1.3`
 - channels(root): `"home-manager-18.09, nixos-18.09.2394.2d656a97297"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

P.S. I run into this issue while trying to install PyMC3

[markuskowa]

It broke with the update of gmock 1.8.0 -> 1.8.1:
https://hydra.nixos.org/api/scmdiff?rev1=0a308534615dc3cbb37f3c9400323a9089083343&uri=https%3A%2F%2Fgithub.jparrowsec.cn%2FNixOS%2Fnixpkgs.git&rev2=a83d61b70864e7b539e129faa8842113b5a55716&branch=&type=git