re PR target/39027 (double floating point suffix of 'd' and 'D' not accepted)

re PR target/39027 (double floating point suffix of 'd' and 'D' not accepted)

gcc/
	PR c/29027
	* c-lex.c (interpret_float): Default (no suffix) is double.

libcpp/
	PR c/29027
	* include/cpplib.h (CPP_N_DEFAULT): Define.
	* expr.c (interpret_float_suffix): Recognize d or D for double,
	return new value for default.
	(cpp_classify_number): Issue pedwarn for use of d or D in suffix.

gcc/testsuite/
	PR c/29027
	* gcc.dg/fltconst-1.c: Don't error for use of d or D in suffix.
	* gcc.dg/fltconst-2.c: New test.
	* gcc.dg/fltconst-double-pedantic-1.c: New test.
	* gcc.dg/fltconst-double-pedantic-2.c: New test.

From-SVN: r145422