Fix compile warnings building previous delta in a 32-bit environment.

Fix compile warnings building previous delta in a 32-bit environment.

	* config/tc-arm.c (is_double_a_single): Make conditional upon the
	availablity of a 64-bit type.  Use this type for the argument and
	mantissa.
	(double_to_single): Likewise.
	* config/tc-arm.c (move_or_literal_pool): Use a 64-bit type for
	the constant value, if available.  Generate a 64-bit value from a
	bignum if supported.  Only perform the second optimization for
	PR 18500 if the 64-bit type is available.