Move architecture shlib-versions files to Linux-specific directories.

Move architecture shlib-versions files to Linux-specific directories.

Various architectures have files such as sysdeps/<arch>/shlib-versions
whose contents are in fact entirely Linux-specific, relating only to
the symbol / shared library versions for the port to Linux on that
architecture, when any future port to a different OS on that
architecture would use the symbol version of the glibc release it goes
in, as standard for new ports.

This patch moves such files under sysdeps/unix/sysv/linux/, merging in
the contents of sysdeps/<arch>/nptl/shlib-versions in the process.
The only bits not moved are those relating to libgcc_s versions, which
don't appear OS-specific in the same way that glibc's symbol versions
so.  It deliberately does not change the regular expressions given for
matching configurations in each file; some match only Linux although
not Linux-specific, or match other OSes although Linux-specific.  It
is with a view to at least the following further cleanups:

* Move architecture-specific content from the toplevel shlib-versions
  and nptl/shlib-versions into sysdeps shlib-versions files, so
  eliminating another difference between ex-ports and non-ex-ports
  architectures.

* Likewise, for OS-specific content in shlib-versions files.

* At that point, the first field in shlib-versions files (the regular
  expression matching a configuration triplet) should be redundant, so
  eliminate that field and leave shlib-versions selection working
  purely on a sysdeps basis (with limited use of %ifdef in
  shlib-versions files when needed) rather than having its own
  separate mechanism to select what configuration information is
  relevant.

* Move the build of gnu/lib-names.h to a similar mechanism to that
  used for gnu/stubs.h (each library build installing a version of the
  header specifically for that build), so we can eliminate the
  duplication of soname information in the makefiles and get it purely
  from shlib-versions files again.

There may be other cleanups possible as well (in particular, I'm not
sure that all cases where the same "Earliest symbol set" information
is repeated for many different libraries actually should need to
repeat it rather than specifying it just once for DEFAULT for the
given configuration, and separately specifying any non-default choices
of soname).

Tested x86_64 that the installed shared libraries are unchanged by
this patch.

	* sysdeps/aarch64/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/aarch64/shlib-versions: ... here.
	* sysdeps/alpha/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/alpha/shlib-versions: ... here.
	* sysdeps/arm/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/arm/shlib-versions: ... here.
	* sysdeps/hppa/shlib-versions: Move all contents except for
	libgcc_s entry to ...
	* sysdeps/unix/sysv/linux/hppa/shlib-versions: ... here.  Merge in
	entry from ...
	* sysdeps/hppa/nptl/shlib-versions: ... here.  Remove file.
	* sysdeps/ia64/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/ia64/shlib-versions: ... here.  Merge in
	entry from ...
	* sysdeps/ia64/nptl/shlib-versions: ... here.  Remove file.
	* sysdeps/m68k/coldfire/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/m68k/coldfire/shlib-versions: ... here.
	* sysdeps/microblaze/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/microblaze/shlib-versions: ... here.
	* sysdeps/mips/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/mips/shlib-versions: ... here.  Merge in
	entry from ...
	* sysdeps/mips/nptl/shlib-versions: ... here.  Remove file.
	* sysdeps/tile/shlib-versions: Move to ...
	* sysdeps/unix/sysv/linux/tile/shlib-versions: ... here.
	* sysdeps/unix/sysv/linux/x86_64/64/shlib-versions: Merge in entry
	from ...
	* sysdeps/x86_64/64/shlib-versions: ... here.  Remove file.
	* sysdeps/unix/sysv/linux/x86_64/x32/shlib-versions: Merge in
	entry from ...
	* sysdeps/x86_64/x32/shlib-versions: ... here.  Remove file.