therubyracer compile failure (gcc4.9)

therubyracer_install_fail

# Using brew installed gcc49 and compiled Ruby using gcc49 therubyracer fails to build
# (it seems to build okay if Ruby is compiled with gcc42)

$ gem install therubyracer -v '0.12.0'

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /Users/nicholas/.rvm/rubies/ruby-2.0.0-p247/bin/ruby extconf.rb
checking for main() in -lpthread... yes
checking for main() in -lobjc... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling accessor.cc
g++-4.9: error: unrecognized command line option '-rdynamic'
make: *** [accessor.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin/gems/therubyracer-0.12.0 for inspection.
Results logged to /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin/extensions/x86_64-darwin-13/2.0.0/therubyracer-0.12.0/gem_make.out
An error occurred while installing therubyracer (0.12.0), and Bundler cannot continue.
Make sure that `gem install therubyracer -v '0.12.0'` succeeds before bundling.

------
$ cat ~/.bash_profile
export ARCHFLAGS="-arch x86_64"
export CC="/usr/local/bin/gcc-4.9"
export CXX="/usr/local/bin/g++-4.9"
export CPP="/usr/local/bin/cpp-4.9"
export CPPFLAGS=-I/opt/X11/include
...

$ ruby -v
ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin13.0.2]

$ gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 2.2.2
  - RUBY VERSION: 2.0.0 (2013-06-27 patchlevel 247) [x86_64-darwin13.0.2]
  - INSTALLATION DIRECTORY: /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin
  - RUBY EXECUTABLE: /Users/nicholas/.rvm/rubies/ruby-2.0.0-p247/bin/ruby
  - EXECUTABLE DIRECTORY: /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin/bin
  - SPEC CACHE DIRECTORY: /Users/nicholas/.gem/specs
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-13
  - GEM PATHS:
     - /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin
     - /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@global
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@admin/bin
     - /Users/nicholas/.rvm/gems/ruby-2.0.0-p247@global/bin
     - /Users/nicholas/.rvm/rubies/ruby-2.0.0-p247/bin
     - /Users/nicholas/.rvm/bin
     - /usr/local/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin