Switch the license of all .h files to GPLv3. Switch the license of all .cc files to GPLv3.
* gdb.cp/virtfunc.cc: Add copyright notice.
* gdb.cp: New directory. * gdb.cp/*: Copy from gdb.c++/*. * gdb.c++/*: Remove. * Makefile.in: Change gdb.c++ to gdb.cp. * configure.in: Ditto. * configure: Regnerate.