Take advantage of new linker from LLVM backend.

Rakefile

@@ -163,7 +163,7 @@ task :make do
     if numjobs.empty?
       case RUBY_PLATFORM
       when /linux/
-        numjobs = (platform == 'web' ? `grep 'core id' /proc/cpuinfo |sort |uniq |wc -l` : `grep -c processor /proc/cpuinfo`).chomp
+        numjobs = `grep -c processor /proc/cpuinfo`.chomp
       when /darwin/
         numjobs = `sysctl -n hw.#{platform == 'web' ? 'physical' : 'logical'}cpu`.chomp
       when /win32|mingw|mswin/