* flags.h : Add new variable flag_single_precision_constant.
        * toplev.c (display_help) : Add -fsingle-precision-constant option.
        (flag_single_precision_constant): New.
        * c-lex.c (yylex): Convert floating point constant to single
        precision constant.
        * invoke.texi : Add documentation for this new option.

From-SVN: r34946