Update copyright dates.

Update copyright dates.

Manual part of copyright year updates.

2021-01-01  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* gcc.c (process_command): Update copyright notice dates.
	* gcov-dump.c (print_version): Ditto.
	* gcov.c (print_version): Ditto.
	* gcov-tool.c (print_version): Ditto.
	* gengtype.c (create_file): Ditto.
	* doc/cpp.texi: Bump @copying's copyright year.
	* doc/cppinternals.texi: Ditto.
	* doc/gcc.texi: Ditto.
	* doc/gccint.texi: Ditto.
	* doc/gcov.texi: Ditto.
	* doc/install.texi: Ditto.
	* doc/invoke.texi: Ditto.
gcc/ada/
	* gnat_ugn.texi: Bump @copying's copyright year.
	* gnat_rm.texi: Likewise.
gcc/d/
	* gdc.texi: Bump @copyrights-d year.
gcc/fortran/
	* gfortranspec.c (lang_specific_driver): Update copyright notice
	dates.
	* gfc-internals.texi: Bump @copying's copyright year.
	* gfortran.texi: Ditto.
	* intrinsic.texi: Ditto.
	* invoke.texi: Ditto.
gcc/go/
	* gccgo.texi: Bump @copyrights-go year.
libgomp/
	* libgomp.texi: Bump @copying's copyright year.
libitm/
	* libitm.texi: Bump @copying's copyright year.
libquadmath/
	* libquadmath.texi: Bump @copying's copyright year.