deps: fix V8 build for GCC 6

[targos]

Checklist

• tests and code linting passes
• a test and/or benchmark is included
• documentation is changed or added
• the commit message follows commit guidelines

Affected core subsystem(s)

build

Description of change

V8 erroneously does null pointer checks on this.
It can lead to a SIGSEGV crash if node is compiled with GCC 6.
Enable -fno-delete-null-pointer-checks to circumvent this issue.

Ref: #6272

cc @bnoordhuis @nodejs/v8 @nodejs/build

[targos]

I wanted to submit this directly to V8 but I am completely unable to build V8 on my computer:

v8 [master] % make x64.release
PYTHONPATH="/home/mzasso/git/chromium/v8/tools/generate_shim_headers:/home/mzasso/git/chromium/v8/build::/home/mzasso/git/chromium/v8/build/gyp/pylib:" \
GYP_GENERATORS=make \
build/gyp/gyp --generator-output="out" build/all.gyp \
              -Ibuild/standalone.gypi --depth=. \
              -Dv8_target_arch=x64 \
               -Dtarget_arch=x64 \
               \
              -S.x64.release  -Dv8_enable_backtrace=1 -Darm_fpu=default -Darm_float_abi=default
make[1]: Entering directory '/home/mzasso/git/chromium/v8/out'
  CXX(target) /home/mzasso/git/chromium/v8/out/x64.release/obj.target/v8_base/src/accessors.o
/home/mzasso/git/chromium/v8/third_party/llvm-build/Release+Asserts/bin/clang++: error while loading shared libraries: libtinfo.so.5: cannot open shared object file: No such file or directory
src/v8_base.target.x64.release.mk:586: recipe for target '/home/mzasso/git/chromium/v8/out/x64.release/obj.target/v8_base/src/accessors.o' failed
make[1]: *** [/home/mzasso/git/chromium/v8/out/x64.release/obj.target/v8_base/src/accessors.o] Error 127
make[1]: Leaving directory '/home/mzasso/git/chromium/v8/out'
Makefile:317: recipe for target 'x64.release' failed
make: *** [x64.release] Error 2

[octoploid]

Just create a symlink from libtinfo.so.5 to libncurses.so.

[bnoordhuis]

Or try make x64.release GYP_DEFINES="-Dclang=0".

[bnoordhuis]

Apropos this PR, can I suggest back-porting the Page::IsValid() / LargePage::IsValid() changes from v8/v8@4e8736d?

-fno-delete-null-pointer-checks is an acceptable-ish workaround but seeing it's fixed upstream, why settle for less?

[targos]

Apropos this PR, can I suggest back-porting the Page::IsValid() / LargePage::IsValid() changes from v8/v8@4e8736d?

Of course. I wasn't aware of these changes when I made the PR. I'm just gonna close this and work on the backport.

[targos]

Or try make x64.release GYP_DEFINES="-Dclang=0".

I get the same error

[bnoordhuis]

Mea culpa, I mistyped. It should be make x64.release GYP_DEFINES="clang=0", without the -D.

[targos]

still not working :(

Edit: I mean it's still trying to run ./third_party/llvm-build/Release+Asserts/bin/clang++

[bnoordhuis]

I don't know what commit you're at but V8's build system is going through some changes right now and it might just be plain broken, see e.g. https://codereview.chromium.org/1938893002/. Maybe try checking out a revision from one or two weeks ago.

[targos]

Oh I see, thank you. I was on master.