* private-options.h: idem.

* private-options.h: idem.

* eval.i.c: copyright nitpicking.

* eval.c: distangle. move duplicate code to eval.i.c and include
twice.

* eval.i.c: new file.

* backtrace.c, debug.c, debug.h, deprecation.c, eq.c, eval.c
eval.h, gsubr.c, init.c, macros.c, print.c, print.h, read.c,
read.h, stacks.c, symbols.c, throw.c: use private-options.h

* private-options.h: new file: contain hardcoded option
definitions.