def cpp_flag(compiler):
standards = ['<STR_LIT>', '<STR_LIT>', '<STR_LIT>']<EOL>for standard in standards:<EOL><INDENT>if has_flag(compiler, [standard]):<EOL><INDENT>return standard<EOL><DEDENT><DEDENT>raise RuntimeError(<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'<EOL>)<EOL>
Return the -std=c++[0x/11/14] compiler flag.
    The c++14 is preferred over c++0x/11 (when it is available).