Copy gdb-gdb.py to build dir

Copy gdb-gdb.py to build dir

I have thought for a long time how nice it would be to have cool pretty
printers for GDB's internal types.  Well, turns out there are few
already in gdb-gdb.py!  Unfortunately, if you build GDB outside of the
source directory, that file never gets loaded.  top-gdb will look for a
file called

  ../path/to/build/gdb/gdb-gdb.py

but that file is in the source directory at

  ../path/to/src/gdb/gdb-gdb.py

This patch makes it so we copy it to the build directory, just like we
do for gdb-gdb.gdb.  With this, I can at least see the file getting
automatically loaded:

(top-gdb) info pretty-printer
global pretty-printers:
  builtin
    mpx_bound128
  objfile /home/emaisin/build/binutils-gdb/gdb/gdb pretty-printers:
  type_lookup_function

I noticed that running "make" didn't re-generate gdb-gdb.py from
gdb-gdb.py.in.  That's because it's copied when running the configure
script and that's it.  I added a rule in the Makefile for that (and for
gdb-gdb.gdb too) and added them as a dependency to the "all" target.

gdb/ChangeLog:

	* gdb-gdb.py: Move to...
	* gdb-gdb.py.in: ... here.
	* configure.ac (AC_CONFIG_FILES): Add gdb-gdb.py.
	* Makefile.in (all): Add gdb-gdb.gdb and gdb-gdb.py as
	dependencies.
	(distclean): Remove gdb-gdb.py when cleaning.
	(gdb-gdb.py, gdb-gdb.gdb): New rules.
	* configure: Re-generate.