MAC OSX 10.15.7 - bundle install failed for rubyracer which depends on libv8 for ruby 2.0.0

Question

I am using ruby-2.0.0-p648 for rails 4.0.0.

Currently working on system macOS Catalina, when I run bundle install it gives following error,

Installing libv8 3.16.14.19 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/ext/libv8
/Users/rex/.rvm/rubies/ruby-2.0.0-p648/bin/ruby -I /Users/rex/.rvm/rubies/ruby-2.0.0-p648/lib/ruby/site_ruby/2.0.0 -r ./siteconf20210419-8256-1q1up44.rb extconf.rb
creating Makefile
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/disable-building-tests.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/disable-werror-on-osx.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/disable-xcode-debugging.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/do-not-imply-vfp3-and-armv7.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/do-not-use-MAP_NORESERVE-on-freebsd.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/do-not-use-vfp2.patch
Applying /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/patches/fPIC-for-static.patch
Compiling v8 for x64
Using python 2.7.16
Using compiler: c++ (clang version 12.0.0)
Unable to find a compiler officially supported by v8.
It is recommended to use GCC v4.4 or higher
Beginning compilation. This will take some time.
Building v8 with env CXX=c++ LINK=c++  /usr/bin/make x64.release ARFLAGS.target=crs werror=no
GYP_GENERATORS=make \
    build/gyp/gyp --generator-output="out" build/all.gyp \
                  -Ibuild/standalone.gypi --depth=. \
                  -Dv8_target_arch=x64 \
                  -S.x64  -Dv8_enable_backtrace=1 -Dv8_can_use_vfp2_instructions=true -Darm_fpu=vfpv2 -Dv8_can_use_vfp3_instructions=true -Darm_fpu=vfpv3 -Dwerror=''
  CXX(target) /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/vendor/v8/out/x64.release/obj.target/preparser_lib/src/allocation.o
clang: warning: include path for libstdc++ headers not found; pass '-stdlib=libc++' on the command line to use the libc++ standard library instead [-Wstdlibcxx-not-found]
In file included from ../src/allocation.cc:33:
../src/utils.h:33:10: fatal error: 'climits' file not found
#include <climits>
         ^~~~~~~~~
1 error generated.
make[1]: *** [/Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/vendor/v8/out/x64.release/obj.target/preparser_lib/src/allocation.o] Error 1
make: *** [x64.release] Error 2
/Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/ext/libv8/location.rb:36:in `block in verify_installation!': libv8 did not install properly, expected binary v8 archive
'/Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/vendor/v8/out/x64.release/obj.target/tools/gyp/libv8_base.a'to exist, but it was not found (Libv8::Location::Vendor::ArchiveNotFound)
    from /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/ext/libv8/location.rb:35:in `each'
    from /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/ext/libv8/location.rb:35:in `verify_installation!'
    from /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19/ext/libv8/location.rb:26:in `install!'
    from extconf.rb:7:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in /Users/rex/.rvm/gems/ruby-2.0.0-p648/gems/libv8-3.16.14.19 for inspection.
Results logged to /Users/rex/.rvm/gems/ruby-2.0.0-p648/extensions/x86_64-darwin-19/2.0.0/libv8-3.16.14.19/gem_make.out

An error occurred while installing libv8 (3.16.14.19), and Bundler cannot continue.
Make sure that `gem install libv8 -v '3.16.14.19' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  therubyracer was resolved to 0.12.3, which depends on
    libv8

Answer 1

Following did not work as v8 was installed via Homebrew and no symlink for following path was created,

gem install therubyracer -v '0.12.3' -- --with-v8-dir=/usr/local/opt/[email protected]

So made it available from Cellar & provided some environment variables needed,

export CXX=clang++
export GYPFLAGS=-Dmac_deployment_target=10.15
gem install therubyracer -v '0.12.3' -- --with-v8-dir=/usr/local/Cellar/v8/8.9.255.25

This worked like charm.