tensorflow: build fail with cuda: identifier "__builtin_ia32_mwaitx" is undefined

Using gcc 5 with cuda support results in a compilation error:

INFO: From Compiling tensorflow/core/kernels/adjust_contrast_op_gpu.cu.cc:

# Omitting warnings

/usr/lib/gcc/x86_64-unknown-linux-gnu/5.3.0/include/mwaitxintrin.h(36): error: identifier "__builtin_ia32_monitorx" is undefined

/usr/lib/gcc/x86_64-unknown-linux-gnu/5.3.0/include/mwaitxintrin.h(42): error: identifier "__builtin_ia32_mwaitx" is undefined

2 errors detected in the compilation of "/tmp/tmpxft_00002a59_00000000-7_adjust_contrast_op_gpu.cu.cpp1.ii".

Build process is as follows:

  TF_UNOFFICIAL_SETTING=1 ./configure <<EOF
/usr/bin/python
y
7.5
/opt/cuda
4.0.7
/opt/cuda
5.2
EOF

    bazel build --jobs 4 --config=cuda -c opt --verbose_failures \
        //tensorflow/tools/pip_package:build_pip_package

The environnement is:

• bazel 0.1.5-1
• cuda 7.5
• cudnn 4
• gcc 5.3.0
• boost 1.60 (is it even relevant?)
• python3.5 (/usr/bin/python is python3)

This issue might be related to boost 1.60 or gcc 5 as mentioned here or there. One suggested fix is to restrict gcc to ansi c++, which can be achieved like so:

diff --git a/third_party/gpus/crosstool/CROSSTOOL b/third_party/gpus/crosstool/CROSSTOOL
index dfde7cd..547441f 100644
--- a/third_party/gpus/crosstool/CROSSTOOL
+++ b/third_party/gpus/crosstool/CROSSTOOL
@@ -46,6 +46,8 @@ toolchain {
   # Use "-std=c++11" for nvcc. For consistency, force both the host compiler
   # and the device compiler to use "-std=c++11".
   cxx_flag: "-std=c++11"
+  cxx_flag: "-D_MWAITXINTRIN_H_INCLUDED"
+  cxx_flag: "-D__STRICT_ANSI__"
   linker_flag: "-lstdc++"
   linker_flag: "-B/usr/bin/"

(btw. thank you @vrv for telling which file to change).

Could anyone please kindly review this, and integrate it (or not)? Note that I am not quite sure wether both flags are actually required and what the side effects might be.