libgfortran: -mabi=ieeelongdouble I/O fix

libgfortran: -mabi=ieeelongdouble I/O fix

The following patch fixes:
FAIL: gfortran.dg/fmt_en.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_en.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_en.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_en.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_en.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_en.f90   -Os  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_en_rd.f90   -Os  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_en_rn.f90   -Os  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_en_ru.f90   -Os  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_en_rz.f90   -Os  output pattern test
FAIL: gfortran.dg/fmt_g0_7.f08   -O0  execution test
FAIL: gfortran.dg/fmt_g0_7.f08   -O1  execution test
FAIL: gfortran.dg/fmt_g0_7.f08   -O2  execution test
FAIL: gfortran.dg/fmt_g0_7.f08   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  execution test
FAIL: gfortran.dg/fmt_g0_7.f08   -O3 -g  execution test
FAIL: gfortran.dg/fmt_g0_7.f08   -Os  execution test
FAIL: gfortran.dg/fmt_pf.f90   -O0  output pattern test
FAIL: gfortran.dg/fmt_pf.f90   -O1  output pattern test
FAIL: gfortran.dg/fmt_pf.f90   -O2  output pattern test
FAIL: gfortran.dg/fmt_pf.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  output pattern test
FAIL: gfortran.dg/fmt_pf.f90   -O3 -g  output pattern test
FAIL: gfortran.dg/fmt_pf.f90   -Os  output pattern test
FAIL: gfortran.dg/large_real_kind_1.f90   -O0  execution test
FAIL: gfortran.dg/large_real_kind_1.f90   -O1  execution test
FAIL: gfortran.dg/large_real_kind_1.f90   -O2  execution test
FAIL: gfortran.dg/large_real_kind_1.f90   -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions  execution test
FAIL: gfortran.dg/large_real_kind_1.f90   -O3 -g  execution test
FAIL: gfortran.dg/large_real_kind_1.f90   -Os  execution test

2022-01-04  Jakub Jelinek  <jakub@redhat.com>

	* io/write_float.def (CALCULATE_EXP): If HAVE_GFC_REAL_17, also use
	CALCULATE_EXP(17).
	(determine_en_precision): Use 17 instead of 16 as first EN_PREC
	argument for kind 17.
	(get_float_string): Use 17 instead of 16 as first FORMAT_FLOAT
	argument for kind 17.