gfortran: Introduce gfc_type_abi_kind

The following patch detects the powerpc64le-linux kind == 16 cases
and for the -mabi=ieeelongdouble case (no matter whether it is the
configured in default or just option used on the command line) uses
_r17 or _c17 instead of _r16 or _c17 in the library API names.

From what I can see, e.g. calls to sin on real(kind = 16) works fine
with or without this patch (we call __builtin_sinl and the backend
uses rs6000_mangle_decl_assembler_name which ensures __sinieee128
is called).

What is clearly still broken is IO, where for
  real(kind=16) a
  a = 1.0
  print *, a
end
we call
  _gfortran_transfer_real_write (&dt_parm.0, &a, 16);
for both -mabi=ibmlongdouble and -mabi=ieeelongdouble
I don't remember what was the agreement, do we want
  _gfortran_transfer_real_write (&dt_parm.0, &a, 17);
for the ieeelongdouble case, or some new entrypoint for
the abi_kind == 17 real/complex IO?
Also, what about kind stored in array descriptors?  Shall we use
there the abi_kind or kind?

I guess at least before the IO case is solved there is no point
in checking the testsuite, too many things will be majorly broken...

2021-12-31  Jakub Jelinek  <jakub@redhat.com>

	* gfortran.h (gfc_real_info): Add abi_kind member.
	(gfc_type_abi_kind): Declare.
	* trans-types.c (gfc_init_kinds): Initialize abi_kind.
	* intrinsic.c (gfc_type_abi_kind): New function.
	(conv_name): Use it.
	* iresolve.c (resolve_transformational, gfc_resolve_abs,
	gfc_resolve_char_achar, gfc_resolve_acos, gfc_resolve_acosh,
	gfc_resolve_aimag, gfc_resolve_and, gfc_resolve_aint, gfc_resolve_all,
	gfc_resolve_anint, gfc_resolve_any, gfc_resolve_asin,
	gfc_resolve_asinh, gfc_resolve_atan, gfc_resolve_atanh,
	gfc_resolve_atan2, gfc_resolve_bessel_n2, gfc_resolve_ceiling,
	gfc_resolve_cmplx, gfc_resolve_complex, gfc_resolve_cos,
	gfc_resolve_cosh, gfc_resolve_count, gfc_resolve_dble,
	gfc_resolve_dim, gfc_resolve_dot_product, gfc_resolve_dprod,
	gfc_resolve_exp, gfc_resolve_floor, gfc_resolve_hypot,
	gfc_resolve_int, gfc_resolve_int2, gfc_resolve_int8, gfc_resolve_long,
	gfc_resolve_log, gfc_resolve_log10, gfc_resolve_logical,
	gfc_resolve_matmul, gfc_resolve_minmax, gfc_resolve_maxloc,
	gfc_resolve_findloc, gfc_resolve_maxval, gfc_resolve_merge,
	gfc_resolve_minloc, gfc_resolve_minval, gfc_resolve_mod,
	gfc_resolve_modulo, gfc_resolve_nearest, gfc_resolve_or,
	gfc_resolve_real, gfc_resolve_realpart, gfc_resolve_reshape,
	gfc_resolve_sign, gfc_resolve_sin, gfc_resolve_sinh, gfc_resolve_sqrt,
	gfc_resolve_tan, gfc_resolve_tanh, gfc_resolve_transpose,
	gfc_resolve_trigd, gfc_resolve_xor, gfc_resolve_random_number):
	Likewise.
	* trans-decl.c (gfc_build_intrinsic_function_decls): Likewise.