v8: fix build errors with g++ 7

[bnoordhuis]

This is a local patch because upstream fixed it differently by moving
large chunks of code out of objects.h. We cannot easily back-port
those changes due to their size and invasiveness.

Node CI: https://ci.nodejs.org/job/node-test-pull-request/7376/
V8 CI: https://ci.nodejs.org/job/node-test-commit-v8-linux/645/

[benjamingr]

test failure is weird and does not happen on my box with this commit (although, with newer clang).

Found this catchorg/Catch2#334

Related issue #12388 , I'm fine with landing as is.

[bnoordhuis]

The test failure:

In file included from ../deps/v8/src/base/functional.cc:11:
In file included from ../deps/v8/src/base/functional.h:11:
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/4.9/cstddef:51:11: error: no member named 'max_align_t' in the global namespace
  using ::max_align_t;
        ~~^
1 error generated.

It's not related to this pull request, it happens intermittently on the clang 3.4.1 buildbot for reasons beyond my ken.

[danbev]

Sorry if this is the wrong place and might be a stupid question...
When reviewing this I wanted to run it locally with g++7, so I installed it (on Mac):

$ g++ -v
gcc version 7.0.1 20170409 (experimental) (GCC)
$ gcc -v
gcc version 7.0.1 20170409 (experimental) (GCC)

Running make I get the following error:

make -C out BUILDTYPE=Release V=1
  c++ '-D_DARWIN_USE_64_BIT_INODE=1' -I../deps/gtest -I../deps/gtest/include  -Os -gdwarf-2 -mmacosx-version-min=10.7 -arch x86_64 -Wall -Wendif-labels -W -Wno-unused-parameter -std=gnu++0x -stdlib=libc++ -fno-rtti -fno-exceptions -fno-threadsafe-statics -fno-strict-aliasing -MMD -MF /Users/danielbevenius/work/nodejs/node/out/Release/.deps//Users/danielbevenius/work/nodejs/node/out/Release/obj.target/gtest/deps/gtest/src/gtest-death-test.o.d.raw   -c -o /Users/danielbevenius/work/nodejs/node/out/Release/obj.target/gtest/deps/gtest/src/gtest-death-test.o ../deps/gtest/src/gtest-death-test.cc
c++: error: unrecognized command line option ‘-stdlib=libc++’
make[1]: *** [/Users/danielbevenius/work/nodejs/node/out/Release/obj.target/gtest/deps/gtest/src/gtest-death-test.o] Error 1
make: *** [node] Error 2

I'm able to force this compile and run the test by setting clang to 0 in common.gypi:

      ['OS=="mac"', {
        'clang%': 0,
      }, {
        'clang%': 0,
      }],

I get the feeling that I'm missing something. If you have any advice I'd appreciated it. I'd like to be able to switch between gcc/clang for future reviews/issues/troubleshooting. Thanks

[bnoordhuis]

I believe -stdlib=... is an apple-clang extension. We assume clang on OS X and set CLANG_CXX_LIBRARY accordingly. You should be able to override it with export CXX=g++ CXX.host=g++ && ./configure -- -Dclang=0.

[danbev]

You should be able to override it with export CXX=g++ CXX.host=g++ && ./configure -- -Dclang=0.

Worked like a charm, thanks!

[kasicka]

Can you merge this into v8 branch too?

[bnoordhuis]

Ambiguity alert: do you mean the node.js v8.0 branch or the upstream V8 project?

If it's the former, I don't remember build issues with g++ 7 but if you have them, file a pull request against the master branch.

If it's V8, you'll have to send the changes to them - although here too I don't remember issues last time I tried.

[kasicka]

I meant node.js v8 branch, latest nightly fails to build on rawhide.