You may be aware that GNU C is under an unusual form of copyright restriction, often called a "copyleft". The details are somewhat confusing, and there is a lot of hype and hyperbole surrounding copyleft and how it might pertain to MPW™ GCC.
NOTE: THE FOLLOWING IS NOT THE LEGAL OPINION OF APPLE OR ANYBODY ELSE!
Simply put, the copyleft is designed to ensure that a freely available program remains freely available. Putting a program in the public domain does NOT prevent an unscrupulous person from slapping a copyright on and attempting to claim ownership. To counter this, the copyleft says that you may freely use, modify, and redistribute a copylefted program, but that you must make available all the source code, and may not restrict the recipients from using, modifying, and redistributing what you give them.
Q: If I modify GCC, do I then have to give my changes away?
A: No. The copyleft does not apply to anything you might do in the privacy of your own machine.
Q: Do programs compiled by GCC fall under the copyleft?
A: No (probably). GCC is merely a translator. However, linking with GNU libraries would cause a program to be copylefted. At present, MPW™ GCC uses only MPW™ libraries and include files, which are unaffected by the copyleft.
Q: What about Bison output?
A: Since Bison output always includes the copylefted Bison parser skeletons (bison.simple or bison.hairy), Bison-generated parsers ARE copylefted.
Q: If somebody just wants the executable, can I give it to them without sources?
A: Yes, as long as you include some info about how to get the sources; a file server location or mail address is good enough.
Q: Who actually holds the legal copyright on GCC?
A: The Free Software Foundation has the copyright on the bulk of GCC, while Apple holds the copyright on those parts of GCC that were written especially for the Mac.
