COMPLEX*16 declarations are non-standard

[Beliavsky]

COMPLEX*16 declarations are non-standard, although they are accepted by many compilers, and they should be replaced by something standard-conforming such as COMPLEX(KIND=16).

COMPLEX*16 declarations are found in many of the codes starting with z, for example zupmtr.f

[mgates3]

complex(kind=16) is a non-portable mechanism that typically means 16-byte real and 16-byte imaginary parts, i.e., quad precision, not double precision. The actual kind values are compiler-dependent. See https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2023-2/complex-16-constants.html

Fortran 90 does provide a portable mechanism. See https://github.com/Reference-LAPACK/lapack/blob/master/SRC/la_constants.f90

Are there any current Fortran compilers that do not accept complex*16?