Error: Failed to build native gem extension <p>I've tried following some of the advice to uninstall libv8 and reinstall it, then run bundle, but it doesn't seem to work. I'm trying to install twitter-bootstrap-rails with less.</p> <pre><code>&gt; gem install libv8 -v 3.16.14.3 -- --with-system-v8 Done installing documentation for after 0 seconds &gt; bundle update Updating git://github.com/seyhunak/twitter-bootstrap-rails.git Fetching gem metadata from https://rubygems.org/......... Fetching additional metadata from https://rubygems.org/.. Resolving dependencies... Installing rake (10.3.1) Using i18n (0.6.9) Using minitest (4.7.5) Using multi_json (1.9.2) Installing thread_safe (0.3.3) Installing tzinfo (0.3.39) Using activesupport (4.0.2) Using builder (3.1.4) Using erubis (2.7.0) Using rack (1.5.2) Using rack-test (0.6.2) Using actionpack (4.0.2) Using mime-types (1.25.1) Using polyglot (0.3.4) Using treetop (1.4.15) Using mail (2.5.4) Using actionmailer (4.0.2) Using activemodel (4.0.2) Using activerecord-deprecated_finders (1.0.3) Using arel (4.0.2) Using activerecord (4.0.2) Using bcrypt (3.1.7) Using bundler (1.5.2) Using coffee-script-source (1.7.0) Using execjs (2.0.2) Using coffee-script (2.2.0) Installing thor (0.19.1) Using railties (4.0.2) Using coffee-rails (4.0.1) Using orm_adapter (0.5.0) Using warden (1.2.3) Installing devise (3.2.4) Using hike (1.2.3) Using jbuilder (1.5.3) Using jquery-rails (3.1.0) Using json (1.8.1) Using kaminari (0.15.1) Using libv8 (3.16.14.3) Using tilt (1.4.1) Using sprockets (2.11.0) Using sprockets-rails (2.0.1) Using rails (4.0.2) Using rdoc (4.1.1) Using ref (1.0.5) Installing sass (3.2.19) Installing sass-rails (4.0.3) Using sdoc (0.4.0) Using simple_form (3.0.2) Using sqlite3 (1.3.9) Gem::Ext::BuildError: ERROR: Failed to build gem native extension. /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/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 clang: warning: argument unused during compilation: '-rdynamic' compiling array.cc clang: warning: argument unused during compilation: '-rdynamic' compiling backref.cc clang: warning: argument unused during compilation: '-rdynamic' compiling constants.cc clang: warning: argument unused during compilation: '-rdynamic' compiling constraints.cc clang: warning: argument unused during compilation: '-rdynamic' compiling context.cc clang: warning: argument unused during compilation: '-rdynamic' compiling date.cc clang: warning: argument unused during compilation: '-rdynamic' compiling exception.cc clang: warning: argument unused during compilation: '-rdynamic' compiling external.cc clang: warning: argument unused during compilation: '-rdynamic' compiling function.cc clang: warning: argument unused during compilation: '-rdynamic' compiling gc.cc clang: warning: argument unused during compilation: '-rdynamic' compiling handles.cc clang: warning: argument unused during compilation: '-rdynamic' compiling heap.cc clang: warning: argument unused during compilation: '-rdynamic' compiling init.cc clang: warning: argument unused during compilation: '-rdynamic' init.cc:11:20: warning: empty parentheses interpreted as a function declaration [-Wvexing-parse] v8::Locker lock(); ^~ init.cc:11:20: note: remove parentheses to declare a variable v8::Locker lock(); ^~ init.cc:11:16: warning: 'lock' has C-linkage specified, but returns user-defined type 'v8::Locker' which is incompatible with C [-Wreturn-type-c-linkage] v8::Locker lock(); ^ 2 warnings generated. compiling invocation.cc clang: warning: argument unused during compilation: '-rdynamic' compiling locker.cc clang: warning: argument unused during compilation: '-rdynamic' compiling message.cc clang: warning: argument unused during compilation: '-rdynamic' compiling object.cc clang: warning: argument unused during compilation: '-rdynamic' compiling primitive.cc clang: warning: argument unused during compilation: '-rdynamic' compiling rr.cc clang: warning: argument unused during compilation: '-rdynamic' compiling script.cc clang: warning: argument unused during compilation: '-rdynamic' compiling signature.cc clang: warning: argument unused during compilation: '-rdynamic' compiling stack.cc clang: warning: argument unused during compilation: '-rdynamic' compiling string.cc clang: warning: argument unused during compilation: '-rdynamic' compiling template.cc clang: warning: argument unused during compilation: '-rdynamic' compiling trycatch.cc clang: warning: argument unused during compilation: '-rdynamic' compiling v8.cc clang: warning: argument unused during compilation: '-rdynamic' compiling value.cc clang: warning: argument unused during compilation: '-rdynamic' linking shared-object v8/init.bundle clang: error: unknown argument: '-multiply_definedsuppress' [-Wunused-command-line-argument-hard-error-in-future] clang: note: this will be a hard error (cannot be downgraded to a warning) in the future make: *** [init.bundle] Error 1 make failed, exit code 2 Gem files will remain installed in /Users/****/.bundler/tmp/63501/gems/therubyracer-0.12.1 for inspection. Results logged to /Users/****/.bundler/tmp/63501/extensions/universal-darwin-13/2.0.0/therubyracer-0.12.1/gem_make.out An error occurred while installing therubyracer (0.12.1), and Bundler cannot continue. Make sure that `gem install therubyracer -v '0.12.1'` succeeds before bundling. </code></pre> <p>I'm not sure what else to do at this point. Should I try uninstalling the gems and reinstalling them?</p>