* tags.h (scm_tags, scm_tc8_tags, scm_tc9_flag, scm_tc8_flag,

	* tags.h (scm_tags, scm_tc8_tags, scm_tc9_flag, scm_tc8_flag,
	scm_tc8_isym): Renamed scm_tags to scm_tc8_tags.  Renamed
	scm_tc9_flag to scm_tc8_flag.  Introduced new identifier
	scm_tc8_isym.  Defined tc8-tags relative to scm_tc3_imm24.
	Defined the tc8-tag for flags to be 0x04, which will mean that
	SCM_BOOL_F will also have the value 0x04 instead of 0x013c.  Due
	to the reduced number of bits and the simpler bit pattern for
	SCM_BOOL_F, certain machines may be able to use more efficient
	processor instructions to deal with SCM_BOOL_F.

	(SCM_ITAG9, SCM_MAKE_ITAG9, SCM_ITAG9_DATA): Removed.  These have
	never been defined in a released version, thus no need to
	deprecate them.

	(SCM_IFLAGP, SCM_MAKIFLAG, SCM_IFLAGNUM): Flags now use tc8
	instead of tc9 tags.

	(SCM_ISYMP, SCM_MAKISYM, SCM_ISYMNUM): Isyms now use tc8 instead
	of tc9 tags.

	(SCM_MAKSPCSYM): Removed.  It is almost impossible that user code
	could have used this definition.

	(SCM_IM_AND, SCM_IM_BEGIN, SCM_IM_CASE, SCM_IM_COND, SCM_IM_DO,
	SCM_IM_IF, SCM_IM_LAMBDA, SCM_IM_LET, SCM_IM_LETSTAR,
	SCM_IM_LETREC, SCM_IM_OR, SCM_IM_QUOTE, SCM_IM_SET_X): Now encoded
	as isyms, as special isyms don't exist any more.