LINKFLAGS take effect. This fixes building shared libraries on 64-bit Linux.

Removed the CCFLAGS from the CXXFLAGS for Linux as SCons combines these
automatically on Linux. This removed the duplication of flags when compiling on
Linux.

On Linux SCons defines CXXCOM as follows

  'CXXCOM': '$CXX -o $TARGET -c $CXXFLAGS $CCFLAGS $_CCCOMCOM $SOURCES'

whereas on Windows it is

  'CXXCOM': '$CXX $CXXFLAGS $CCCOMFLAGS'

Review URL: http://codereview.chromium.org/2422

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@284 ce2b1a6d-e550-0410-aec6-3dcde31c8c00