Freeness of vague Synopsys license
I am currently working on reintroducing GHDL into Debian. It is a VHDL
compiler/simulator that includes non-standard VHDL libraries from
various vendors and I have to throw out most of them (unlike before, it
now comes with the core standard libraries reimplemented under a free
license). I'm now unsure whether I should keep the Synopsys libraries
which found some wider use before its features were finally offered by
the VHDL language standard.
Here is the copyright statement and license from one of the files in its
| Copyright (c) 1990, 1991, 1992 by Synopsys, Inc. All rights reserved.
| This source file may be used and distributed without restriction
| provided that this copyright statement is not removed from the file
| and that any derivative work contains this copyright notice.
It offers use and distribution without restriction, but technically not
explicitly modification. However, if permission of modification weren't
intended, the requirement of keeping the copyright statement would be
pointless. Therefore I am leaning towards permission of modification
Keeping these files would be "nice to have" but not a requirement. Users
with legacy VHDL projects using Synopsys libraries would need to find
and install these libraries themselves if they were removed.