* src/lisp/os.h
   * Move macros and definitions for FPU save/restore from here.
 * src/lisp/arch.h
   * Put architecture neutral stuff from os.h here.
 * src/lisp/ppc-arch.h
 * src/lisp/sparc-arch.h
 * src/lisp/x86-arch.h
   * Implement the FPU save/restore macros here for each supported
     architecture.

 src/lisp/gencgc.c:
 * Move the macros for fpu buffers from gencgc.c to here.
 src/lisp/x86-arch.c:
 * Use the new save_fpu_state instead of fpu_save.  And apply to all
   OSes.

On Linux, os_init can re-exec lisp to set up the correct personality.
Not normally a problem, but if any output happens before os_init is
called, the output appears to happen twice.  So add os_init0 to do
this early on, before any output.  This is a bit of a kludge.

lisp/lisp.c:
o Call os_init0 early in main.

lisp/Linux-os.c:
o Move the personality stuff from os_init to os_init0.

lisp/Darwin-os.c:
lisp/FreeBSD-os.c:
lisp/NetBSD-os.c:
lisp/OpenBSD-os.c:
lisp/hpux-os.c:
lisp/irix-os.c:
lisp/mach-os.c:
lisp/osf1-os.c:
lisp/solaris-os.c:
lisp/sunos-os.c:
o Add dummy implementation of os_init0.  These OSes don't (currently)
  need anything special.

lisp/os.h:
o Declare os_init0.

registers. The test is a stub on everything except NetBSD for now.

in backtrace.c about undeclared function.

o Follow CMUCL coding style.
o Argv and envp are const char*.

os.h:
lisp.c:
Darwin-os.c:
FreeBSD-os.c:
NetBSD-os.c:
OpenBSD-os.c:
hpux-os.c:
irix-os.c:
mach-os.c:
osf1-os.c:
solaris-os.c:
sunos-os.c:
o argv and envp are const char *.

    When run on a kernel compiled without COMPAT_BRK CMUCL segfaults,
    so I copied the kludge used by SBCL - check the current
    personality, and if necessary, enable ADDR_NO_RANDOMIZE and
    re-exec itself.

Linux-os.c:
o Check for personality and rexec if necessary.

os.h:
o New prototype for os_init needed because it needs argv and envp.

lisp.c:
Darwin-os.c:
FreeBSD-os.c:
NetBSD-os.c:
OpenBSD-os.c:
hpux-os.c:
irix-os.c:
mach-os.c:
osf1-os.c:
solaris-os.c:
sunos-os.c:
o Update call to os_init, which needs argv and envp now.

x86-vm.lisp declares os_sigcontext_fpu_modes to return a 32-bit int.

code.  Rather than introduce a new FreeBSD case to the x86 sigcontext
member accessor routines, collapse all of the system specific routines
down to a common set of routines.

* code/debug-int.lisp - Disable some Darwin-specific code to debug
  NULL mcontext pointers.

* code/float-trap.lisp - Remove ancient FreeBSD-specific code for
  handling floating point signals.

* code/macros.lisp, code/sap.lisp, compiler/saptran.lisp - Include the
  SAP-REF-LONG setter by default on the x86.

* code/x86-vm.lisp - Remove operating system specific sigcontext
  definitions and sigcontext accessors.  Define the alien sigcontext
  as a system area pointer.  Replace the sigcontext accessors with
  foreign function calls that mask the complexity of the underlying
  sigcontext member access.

* compiler/x86/float.lisp - Unconditionally define STORE-LONG-FLOAT.
  This function is used by the %SET-SAP-REF-LONG VOP that underlies
  the SAP-REF-LONG setter.

* compiler/x86/sap.lisp - Unconditionally define %SET-SAP-REF-LONG.
  In the case where there is not a distinct LONG-FLOAT type, admit
  DOUBLE-FLOAT values instead.  The x87 automatically widens values
  pushed onto stack.  This mirrors the behavior of the SAP-REF-LONG
  VOP.

* lisp/Darwin-os.c, lisp/Linux-os.c - Define functions to access
  sigcontext members of interest to Lisp.  Delete the sc_reg function
  and replace its uses with os_sigcontext_reg which is more suitably
  typed.

* lisp/FreeBSD-os.c - Define functions to access sigcontext members of
  interest to Lisp.  We need to be careful about the SSE and non-SSE
  cases for retrieving x87 registers from the saved machine state.
  Define a low-level SIGFPE handler to intercept floating point traps
  and restore the cleared status word bits based on the signal code.
  Get rid of sc_reg for the reasons noted above.

* lisp/Darwin-os.h, lisp/FreeBSD-os.h - Declare the restore_fpu
  function and define a specialized RESTORE_FPU macro.  Remove the
  sc_reg prototype.

* lisp/Linux-os.h - Remove the sc_reg prototype.

* lisp/os.h - Add prototypes for the new os_sigcontext functions.

* lisp/x86-lispregs.h - Redefine SC_REG and SC_PC to expand out to the
  new os_sigcontext functions.  Redfine SC_SP to expand out to SC_REG.
  Eliminate all platform-specific defintions of SC_PC and SC_SP.

sigcontext before calling back into Lisp.  The rounding mode is always
set correctly when we reenter Lisp through call_into_lisp.  We now
ensure that the trap bits enabled by the user are also preserved.

all of its remaining references.

.indent.pro.

lisp.c into the correct <foo>-os.h files.

versions of all the required things, this commit separates the
interrupt handler proper (now interrupt_handle_now_handler) from the
actual work-horse (interrupt_handle_now), which is now only ever called
from the two interrupt handlers, interrupt_handle_now_handler and
maybe_now_maybe_later.  This follows similar changes in SBCL, and is in
fact needed in order to properly use sigreturn in signal handlers, as
required to work around a problem with the G5.

	* lisp/sunos-os.h (PROTECTION_VIOLATION_SIGNAL): Define it for
	stack-checking.

	* lisp/solaris-os.c (segv_handler): Add stack-checking support for
	Solaris.

	* lisp/os.h (os_control_stack_overflow): Give a type name to the
	zone enums (mostly for the debugger).

	* lisp/os-common.c (guard_zones): Add stack-checking support for
	Solaris.
	(os_control_stack_overflow): Add stack-checking support for
	Solaris.

	* lisp/interrupt.c (build_fake_control_stack_frame): New function
	for building a stack frame without the foreign call stuff.  Used
	for stack checking.
	(interrupt_install_low_level_handler): Only need to install
	alternate signal stack for x86.

	* lispinit.lisp:
	(scrub-control-stack): Rename to %scrub-control-stack to match x86
	version so control stack guard is done.

	* parms.lisp (static-symbols): Added new static symbols for
	control stack checking.

	feature :stack-checking because it's not implemented for other
	systems/architectures yet.  It is currently known to work on
	FreeBSD 4.8-RC/x86 and Debian 2.2.20/x86.

	* bootfiles/18e/boot3.lisp: New boot file, well, only a
	description of the boot procedure since no boot file is needed.

	* lisp/x86-validate.h (SIGNAL_STACK_START, SIGNAL_STACK_SIZE)
	[__FreeBSD__, __linux__]: New defines.
	(CONTROL_STACK_SIZE) {__FreeBSD__, __linux__]:
	Adjust for signal stack.

	* lisp/validate.c (validate) [RED_ZONE_HIT]: Call
	os_guard_control_stack.  Some cleanup.

	* lisp/os.h (BOTH_ZONES, YELLOW_ZONE, RED_ZONE): New enums.
	Add function prototypes.

	* lisp/interrupt.c (interrupt_install_low_level_handler)
	[RED_ZONE_HIT]: Deliver protection violations on a dedicated
	signal stack.

	* lisp/os-common.c (os_stack_grows_down_1, os_stack_grows_down):
	New functions.
	(guard_zones, control_stack_zone, os_guard_control_stack)
	(os_control_stack_overflow) [RED_ZONE_HIT]: New functions.
	(os_control_stack_overflow) [!RED_ZONE_HIT]: Dummy function.

	* lisp/Linux-os.c (sigsegv_handler) [RED_ZONE_HIT]: Handle control
	stack overflows.

	* lisp/FreeBSD-os.c: General cleansing.
	(sigbus_handler) [RED_ZONE_HIT]: Handle control stack overflows.

	* lisp/FreeBSD-os.h (PROTECTION_VIOLATION_SIGNAL): New define.

	* lisp/Linux-os.h (PROTECTION_VIOLATION_SIGNAL): New define.

	* compiler/x86/system.lisp (lisp::%scrub-control-stack): Change
	defknown from sys:scrub-control-stack.
	(%scrub-control-stack): Rename VOP.

	* code/lispinit.lisp (os-guard-control-stack) [#+stack-checking]:
	Define alien os_guard_control_stack.
	(%scrub-control-stack) [#+x86]: New function.
	(scrub-control-stack) [#+x86]: Call %scrub-control-stack,
	call os-guard-control-stack if #+stack-checking.

	* code/interr.lisp (yellow-zone-hit,
	red-zone-hit) [#+stack-checking]: New functions.

	* code/error.lisp (stack-overflow) [#+stack-checking]: New
	condition.

	* compiler/generic/new-genesis.lisp (finish-symbols)
	[#+stack-checking]: Add symbols for control stack checking.

	* compiler/x86/parms.lisp (static-symbols): Likewise.

On x86 FreeBSD and Linux, change the way foreign symbol addresses are resolved.
They now go through a table -- effectively a new space in the core file.
Function references are resolved lazily, data references are resolved on startup
and when a .so is loaded.  The end result is that cores can be dumped that
contain references to symbols in shared libraries.  Also, the dependence of the core on addresses in the Lisp runtime is broken.

The linkage table feature is controlled by :linkage-table and LINKAGE_TABLE in C
runtime.  Several foreign symbols are now Lisp static symbols, so a cross
compile is required whether or not the new stuff is used.  I've checked in
boot4-cross-foreign-linkage.lisp that builds the compiler for linkage table; do whatever you usually do for the non-linkage table case:)  Seriously, lets start
a discussion on standardizing "cross compilation," not to mention the general
build procedure.

was already cleaned up with the OpenBSD port, this doesn't require
massive changes.

Since current NetBSD is ELF-based by default, we don't make use of the
ELF feature, or in other words:  The presence of the NetBSD feature
implies ELF, since there is no support for non-ELF NetBSD.

code which were previously conditionalized on :FreeBSD, are now
conditionalized on :BSD instead, with the :BSD feature now implying a
4.4BSD(lite2) derived OS.  This should make future BSD-ports easier.
FreeBSD and OpenBSD are differentiated by having either :FreeBSD or
:OpenBSD on the features list.

Currently the OpenBSD port does not have working ELF support, because
OpenBSD 2.9 is still non-ELF by default.  So don't put ELF on the
features list when building for OpenBSD, or fix the code to work
correctly in this case instead.

via the POSIX_SIGS conditional. Change the way SA_SIGINFO gets passed
to sigaction. It is turned off for FreeBSD and Linux.