Adapt support for SSE registers in Linux/x86 for Linux 2.4.

Adapt support for SSE registers in Linux/x86 for Linux 2.4.
* i386-linux-nat.c: Various doc fixes.  Include "i387-nat.h".
(GETFPXREGS_SUPPLIES): Renamed from GETXFPREGS_SUPPLIES.
(have_ptrace_getfpxregs): Renamed from have_ptrace_getxfpregs.
(convert_to_gregset): Removed.  Moved logic to ...
(fill_gregset): ... here.  Simplified function.
(fetch_regs): Use perror_with_name for error reporting.
(store_regs): Add `regno' parameter.  Use perror_with_name for
error reporting.  Call fill_gregset instead of convert_to_gregset.
(FPREG_ADDR): Remove.
(supply_fpregset): Implement by calling i387_supply_fsave.
(convert_to_fpregset): Remove.
(fill_fpregset): Implement by calling i387_fill_fsave.
(fetch_fpregs): Use perror_with_name fro error reporting.
(store_fpregs) Add `regno' parameter.  Use perror_with_name fro
error reporting.  Call fill_fpregset instead of
convert_to_fpregset.
(supply_xfpregset, convert_to_xfpregset): Removed.
(supply_fpxregset, fill_fpxregset): New functions.
(fetch_fpxregs): Renamed from fetch_xfpregs.  Use perror_with_name
for error reporting.  Call supply_fpxregset instead of
supply_xfpregset.
(store_xfpregs): Removed.
(store_fpxregs): New function.
(fetch_inferior_registers): Adjust for xfp -> fpx change.  Tweak
message in call to internal_error.
(store_inferior_registers): Adjust for xfp ->fpx change.  Pass
REGNO to store_regs, store_fpregs and store_fpxregs.
(fetch_core_registers): Adjust for xfp -> fpx change.
* acconfig.h (HAVE_PTRACE_GETFPXREGS): Renamed from
HAVE_PTRACE_GETXFPREGS.
* config.in: Regenerated.
* configure.in: Replace check for PTRACE_GETXFPREGS with check for
PTRACE_GETFPXREGS.  Remove comment about Cygnus SSE extensions.
* configure: Regenerated.
* config/i386/linux.mh (NATDEPFILES): Add i387-nat.o.
* config/i386/tm-linux.h: Base definition of HAVE_SSE_REGS on
HAVE_PTRACE_GETFPXREGS instead of HAVE_PTRACE_GETXFPREGS.