re PR fortran/28276 (EXPONENT() broken for real constants)
* configure.in: Check for GMP 4.1 or newer. Check for MPFR 2.2.0
or newer.
* configure: Regenerated.
* doc/install.texi: Document required versions of GMP and MPFR.
* fortran/arith.c: Conditionally include arctangent2().
(gfc_check_real_range): Use mpfr_subnormalize in preference to local
hack.
* fortran/trans-intrinsic.c (gfc_get_intrinsic_lib_fndecl): Append
l for long double functions.
* fortran/simplify.c: Wrap Copyright to new line.
(gfc_simplify_atan2): Use mpfr_atan2 in preference to arctangent2().
(gfc_simplify_log): Ditto.
PR fortran/28276
* fortran/simplify.c (gfc_simplify_exponent): Use mpfr_get_exp in
preference to broken local hack.
PR fortran/27021
* fortran/simplify.c (gfc_simplify_nearest): Use mpfr_nexttoward and
mpfr_subnormalize to handle numbers near zero in preference to broken
local hack.
PR fortran/28276
* testsuite/gfortran.dg/exponent_1.f90: New test.
PR fortran/27021
* testsuite/gfortran.dg/nearest_1.f90: New test.