Aminet 18/aminetcdnumber181997.iso/Aminet/dev/gcc/ixemulsrc.lha/ixemul/NEWS

Text File | 1997-01-01 | 29KB | 691 lines

============
VERSION 45.1
============

Fixed a bug in the Unix Domain socket code that would occasionally cause a
client to wait indefinately for a connection to be granted, while in fact
the server had already accepted the connection.

getdtablesize() now returns FD_SETSIZE instead of NOFILE (256 instead of
512). The result of this function was used by several X clients to discover
the number of filehandles select() can test. And if that value is to large,
you'll get unexpected and hard to find crashes. The same change was made to
sysconf(_SC_OPEN_MAX).

shutdown() could close down the whole Unix domain socket, causing a
crash when the socket was closed a second time by the 'real' close.

rename() now tests for a rename across devices and returns the correct
error code.

Applied patch from Norbert Pueschel to improve delayed unlink.

Closing of Unix domain sockets is now atomic (between Forbid/Permit),
otherwise the Amiga could crash if the X server was running at a higher
priority than the client.

Fixed a bug in ixemul.trace that caused Enforcer hits in gcc.

Fixed a bug with 'du -ks /volume'. The convert_dir() function stored the
directory name in Amiga format instead of Unix format.

Norbert Pueschel greatly improved uid/gid handling in ixemul.library. See
the README for detailed information.

Fixed a bug in handling volumes/devices named "dev:". Ixemul handles the
volume /dev specially (e.g., /dev/console is translated to console:) and
that interfered with the handling of the DEV:  device or any volume named
DEV:.  To circumvent the /dev handling you can now use "dev:" instead of
"/dev" or write "DEV" instead of "dev" (in other words, the open() function
tests for the string "/dev/" in a case-sensitive way).

Due to a clumsy design of the ENV: notification a signal was occasionally
left unfreed. WShell gives warnings for that, so I changed the design and
that should take care of the warning. The unfreed signal warning was
harmless, but annoying.

Now fill the file type in the dirent struct. Thanks to Lars Hecking for
reporting this.

Some AmigaOS programs started from an ixemul program set Signals that were
allocated by ixemul. This can happen because ixemul resets the allocated
signal mask in the Task structure.  Because of that a handshake between the
child and the parent when the child process is dying failed, and Enforcer
hits (usually followed by a crash) were the result.  Fixed by resetting all
Signals.

Fixed a bug in the trap.s supervisor() code: you cannot safely pass data on
the stack to the function to be executed in supervisor mode. In fact, this
failed with a beta version of the 68060.library from Phase 5. Now pass the
data through registers.

Fixed bug in frexp(0.0, &i) where i was set to 1 instead of 0.

Fixed 32 Kb memory leak.

Added tty CRMOD support.

Fixed serious bug in unix domain sockets where a kind of deadlock situation
could occur.

system() now searches the whole path for 'sh' and doesn't use /bin/sh only.
Also the paths in paths.h have been ADE-dified. Thanks to Robert Davis for
pointing out the system() problem.

select() on a small file that was stored in memory if the user selected a
non-zero Membuf size in ixprefs didn't produce the expected results. Thanks
to Stefan Grosse Pawig for reporting this.

============
VERSION 45.0
============

Moved popen() and pclose() into ixemul.library from libc.a. These functions
are used regularly by libraries, and having them in ixemul.library makes
the conversion of those static libraries into shared libraries easier.
Besides, these functions are used frequently enough to warrant their
integration into ixemul.library.

Added a patch from Kamil Iskra that fixes problems with -mstackextend and
vfork2(). However, such programs *must* call vfork_setup_child().

Thanks to Lars Hecking, a new fnmatch(3) with extended functionality is
available. The fnmatch code is copied from the NetBSD sources.

Added new manual pages.

Upgraded ixemul to the new structure passing scheme of gcc (A1 contains a
pointer to the return structure). This involved ldiv(), div() and
inet_makeaddr(). Thanks to Kamil Iskra for providing me with patches to
implement this.

Upgraded the timezone stuff to the latest version.

Implemented Unix Domain sockets. Missing features: datagrams aren't
(yet?) supported, and connect() doesn't have a timeout.

Removed stack watcher code. It was seldom used, and it was never very
reliable.

Implemented sessions. This improves Ctrl-C handling, and is required to
make full use of xterm.

Fixed an unlink bug (it has to check all open files for the given filename)
and a bug in ix_lock_base/ix_unlock_base: if these calls were nested, the
signal masked was restored to ~0 instead of the original value.

Added a new utility, ixstack, and a new global variable, __stack, to allow
the user and programmer to specify a minimum stacksize. If the current
stack is too small, a new stack is automatically allocated. Thanks to Kamil
Iskra for implementing this.

ioctl(fd, TIOCGPGRP, ...) now returns something useful. NcFtp didn't show
the progress bar anymore because of this.

Added large-baserel libraries and startup-code.

============
VERSION 44.0
============

Kriton Kyrimis updated ixprefs.

David Zaroski updated ixtrace.

Fixed link count for directories. Thanks to Norbert Pueschel.

umask implemented for for open() and mkdir(). Thanks to Norbert Pueschel.

Added muFIBB_SET_GID, which will be implemented in the next version
of MultiUser. The old way of handling setgid was confusing and even
potentially dangerous.  Thanks to Norbert Pueschel.

Added the translation unix sticky bit -> AmigaOS h bit. This one is
more for aestaethical reasons, as the h bit is no longer supported in 3.x.
Thanks to Norbert Pueschel.

Added a field 'void *u_user;' near the beginning of the user struct which
everybody is free to (ab)use. It can be handy to store task private data
in the user struct, at least, I had to use it recently.

Added an ix_amiga.h header, which will contain all amiga specific functions
and macros in ixemul.library and libc.a, together with a description.

Profiling has been enhanced. Ixprefs adds a new profiling preference:
either take samples only while your program is running and the PC is within
your program, or take samples while your program is running and if the PC
is outside your program code (e.g. in ixemul or in intuition.library), use
the last function your program entered before calling ixemul or whatever,
or always take samples, even if other programs are running.  Again, the
last recorded function gets the hit in those cases.

An array of 100 longs to store the A4 register of shared libraries has been
added to the user struct. This array can be easily increased in future
releases, should the need arise. The first 20 slots are for your own free
use, the other slots should be registered. See the file REGISTRY in the
ixemul source distribution for more details.

Fixed yet another path bug. Running a shell script that's placed somewhere
in your PATH from 'make' failed, unless the filename of the script was
absolute.

Added vfork_setup_child to libc.a. This is a wrapper intended to make life
just a little bit easier for those who need to use the vfork2()/vfork_resume()
trick. It replaces the old 'ix_resident()/ix_get_vars2()' pair.

Fixed more problems with the routines that start a shell script. This time
problems with symbolic links have been fixed.

Fixed problems when parsing a pathname of a shell script, preventing the
execution of that script.

Replaced the stdio-sources by the NetBSD 44.0 versions, which incidentally
fixed the broken fgetpos function. This change also adds printf() and scanf()
support for the 'long long' datatype.

Added support for the O_CASE open() flag: this will open an existing file
only if the filenames match using a case-sensitive comparison.

fstat() didn't compensate the file time for the current timezone offset.

Ixemul now supports the 68010 CPU. Thanks to Pascal Eeftinck for pointing
out that the 68010 uses a 68020-like stackframe.

Build the version.[ch] files in the build directory instead of in the
source directory.

Fixed fchdir().

Changed the machine name as returned by uname() to "m68k". Thanks to Lars
Hecking for this.

O_ASYNC I/O is now partially supported: select() will test for this
situation.

/dev/tty is now translated to console:.

Implemented pseudo-terminals support using the FIFO device.

Many, mostly small, changes to become more NetBSD compatible. Where
possible, I've replaced the old sources with the NetBSD 1.1 sources.

The select() function has been improved: it is now much faster and works
much better.

Using F_SETFL with fcntl() failed if the file wasn't a regular file. It now
also works for pipes and sockets.

Requesters that are from ixemul.library or ixnet.library now have the name
of the library as their title, so that you can see that they are from the
library, and not from the application. Thanks to Udo Schnurpfeil for
suggesting this.

The tty database functions unfortunately slipped through and weren't
included with 43.1. They are back in 44.0.

Implemented mmap() and friends. Of course, any mmap feature that actually
requires a MMU will return an error. But if mmap() is used to load a file
into memory, then it works fine.

============
VERSION 43.2
============

Applied patch from Kamil Iskra to improve ixemul stack extension
handling.

============
VERSION 43.1
============

Ixemul no longer uses async writes. All I/O is now synchronous. This
allowed me to remove several Disable()/Enable() pairs, and actually made
ixemul faster. Apparently the overhead in handling async I/O was
substantial.

Applied patches from Jeff Shepherd fixing various problems in the
ixnet.library. Among them improved AS225 passwd handling.

Moved the resolver functions out of ixnet.library into libc.a. All programs
that used these functions will have to be recompiled. Very few programs use
these functions, and since they are really higher level functions and do
not belong in a low level library like ixnet, I've moved them.

Also moved tty database functions (getttyent() and friends, ttyname() and
ttyslot()) to libc.a, for much the same reason.

Added the NetBSD DB sources to libc.a and removed the hacked versions from
ixnet.

Replaced various headers with the NetBSD versions. Important for certain
socket-related ioctl defines that were incorrect in the old headers.

Added ptrace(GETA4, pid, 0, 0) to obtain the value of the a4 register if
this executable was compiled with -fbaserel or -resident. Needed by gdb to
find out where the data section is.

Added ptrace(GETEXENAME, pid, 0, 0) to obtain the name of the current
executable. Useful in scripts that start with '#!/bin/sh' or something
similar. 'argv[0]' as seen by sh is the name of the script, but if you want
to get the pathname of 'sh' itself, you can use this ptrace call.

Added setlocale() and ctermid() to libc.a.

It is now possible to unlink() a file that is owned by another process
(just like Unix). Gcc uses this to remove temporary files that are actually
owned by cpp (or as). Of course, on the Amiga this is implemented as a
delayed delete, i.e. a flag is set in the 'struct file' to tell ixemul to
delete the file when it is closed by the owner process.

Added support for a root ('/') directory. This will only work for programs
that use ixemul.library. So if you start pdksh, 'cd' to the root (cd /) and
use the AmigaOS command 'list' to view this directory, then you won't get
what you expect. If you use the Unix ls command however, then you will see
all the volumes that you have as top level directories.

Removed an old hack in __wait_packet.c that interfered with Ctrl-F
handling.

Fixed a bug in fnctl(), F_SETFL.

Added AFS, AFSFloppy and PFS support.  Many thanks to the AFS author,
Michiel Pelt, who provided me with the necessary technical information, and
to Kriton Kyrimis for giving some very useful suggestions.

Added MultiUserFileSystem support, contributed by Mike Krings. Thanks Mike!

Added new function ix_warning: similar to ix_panic, but allows the user to
choose between "Continue" and "Abort". This to work around a case like:

    for (;;) crypt();

where one couldn't break out of the program because the requester kept
popping up.

Fixed -mstackcheck support and fixed buggy baserel-stackextend support.

The call socket(AF_UNIX, SOCK_STREAM, 0) no longer crashes if ixnet.library
is not installed.

Reorganized Makefiles. I've removed the option to compile each source
separately, instead they are always catenated together. Also, 'make' no
longer starts itself two more times in order to make the library. I've
used GNU make wizardry to let 'make' figure out all the targets by itself.

Sigsetjmp and siglongjmp were broken. Fixed.

Replaced the old man pages with the new NetBSD manual pages in the original
troff form.

Replaced the nice() stub in ix_stub with nice.c from NetBSD.

Removed a Delay(100) that was called just before a vfork()ed program finally
terminated.

Made h_errno a global variable like errno.

At several places in the library the errno variable was reset to 0.
However, the library should (almost) never set errno to 0. This caused
problems with the 'ping' program, where recvfrom set errno to 4, but the
library changed it back to 0 before 'ping' got to see it.

Now sets st_uid and st_gid from a 'stat' structure to the effective UID and
GID. Some programs tested these fields and they failed when using
networking support. These fields used to be 0.

Reread the global environment variables only when 1) a new program is
started, and 2) the ENV: directory has been changed (i.e., a new setting
was added to ENV:). ENV: used to be read every time a program was started,
whether it was needed or not.

Given the shell script s.sh in /ram/t:

    #!/bin/sh
    /bin/echo $0

'sh /ram/t/s.sh' produced '/ram/t/s.sh', while typing '/ram/t/s.sh' from
within the pdksh shell produced 'Ram:t/s.sh'. Fixed.

Removed a dubious CurrentDir() to a *file* instead of a directory.  While
this is apparently supported for the standard AmigaOS filesystems, not all
third-party filesystems supported this.

When you try to use a >68020 ixemul.library on a 68000 Amiga, you now get a
decent message instead of a crash.

============
VERSION 43.0
============

Integrated Jeff Shepherd's networking code. If ixnet.library is installed,
then ixemul.library will use the networking functions from the
ixnet.library, instead of the default dummy implementation. Ixnet.library
works with AS225 and with AmiTCP. It supports both clients and daemons.
A program that uses networking functions is completely shielded from the
AS225 and AmiTCP differences by ixnet.library. That library will take care
of all the details for you. That means that there is no longer any need to
provide two different binaries, one for AS225 and one for AmiTCP.
Furthermore, it is relatively easy to add support for other network
packages. Thanks, Jeff!

Added stackchecking and extension code, thanks to Matthias Fleischer.

Finalized GDB support.

============
VERSION 42.1
============

Fixed bugs when running non-ixemul programs from tools like pdksh or make.
You could get Enforcer hits and the Ctrl-C support also crashed the Amiga.

Use the NetBSD code for the system() function instead of using the Amiga
kernel function SystemTagList. This was the cause of several
incompatibilities when porting Unix programs.

Improved termios support (added OPORT and ONLCR flags and the INLCR flag).

Fixed ptrace handling. Almost none of Leonard's code has survived, I used a
completely different method.

Fixed a problem where the name of the current directory, as is visible
by the shell, wasn't changed when a program terminated and ixemul reset the
current directory to its original place.

Improved performance somewhat by no longer going through address 4 to get
to the ExecBase structure. Instead, it's copied once to the SysBase
variable, and thereafter only that variable is used. The Enforcer manual
warned against accessing address 4 too often, and ixemul.library did that
a lot.

Also improved performance by fixing a busy wait. At one point in the
ixemul, the program cannot continue until a context switch has taken place.
So ixemul waits until the dispatch count of ExecBase has changed,
indicating that a context switch has taken place. By installing a small,
high priority (9) task with body "for (;;) Wait(1 << 31);" and signalling
that task whenever a context switch is needed, I was able to circumvent the
busy wait loop. Because of the high priority of the Task, a context switch
would take place immediately. The task itself goes back to sleep at once,
so there is no time lost there.

============
VERSION 42.0
============

Installed patch in arith.c to work around bug in IEEEDPCmp.  If the first
32 bits of both doubles are equal, and both doubles are negative, then
the result can no longer be trusted.  Discovered by Bart Van Assche.

Ixtrace has been updated to recognize all 42.0 syscalls, thanks to David
Zaroski.

Ctrl-C handling worked with KingCON, but not with the standard AmigaOS
CON-handler (since I use KingCON I never noticed this until it was pointed
out to me by Fred Fish :-). This has now been fixed. See the comments in
library/__read.c for more information.

Added the uname() function, written by Lars Hecking.

The termios code now properly recognizes the ICRNL input flag for '\r' to
'\n' translation.

Fixed a bug in the fcntl() function (actually, in the fcntl.h and
sys/fcntl.h headers).

Moved several static variables to user.h, so they are now process-specific.

Added profiling support. It was always there, but it was never actually
used.

The write() function writes its buffer line-by-line instead of in one big
chunk if the filehandle is the handle of an interactive stream (for
example, a console window). This allows the user to interrupt the output by
pressing a key and it also allows the use of Ctrl-C to break the program.
In previous versions you were unable to stop the output if you forgot to
redirect it to a file. E.g., 'cat /libs/ixemul.library' would essentially
take over the computer.

Changed default stack size handling when a new process is launched. It is
either the value of the environment variable IXSTACK, or it inherits the
size from its parent, but if that size is less than 16384, it uses a stack
of 16384 bytes instead.

Replaced ixconfig by ixprefs (written by Kriton Kyrimis).

Integrated the partial ptrace support from Leonard Norrgard.

Removed the gnulib, gnulib-68881 and gnulib-soft-float directories.

Compiled with -Wall and fixed (nearly) all warnings. Some warnings are
inevitable and cannot be avoided. -Wall already caught one illegal memory
access bug in __Close()!

Added functions to set and get ixemulbase-private information. This will
break older ixconfig's but is much cleaner. Nearly all of the ixemulbase
structure is now off-limits and liable to change without notice! You are
warned! In fact, the structure has been changed already. The library will
complain if a program called 'ixconfig' tries to use it to prevent the user
from using an old ixconfig with the new library.

Removed several arithmetic functions dealing with 'long long' types. They
didn't belong in the library, link with libgcc.a instead. Also removed some
arithmetic functions that are never called because they are compiled
directly in 68000 assembly. Don't know why they were ever added.

Fixed gen_glue.c so that it no longer generates glue for obsolete functions.

Removed ssystem(). ssystem() was the precursor of vfork/execve, and is no
longer needed. NOTE: it is still used in gcc. But this fails spectacularly
once you use Ctrl-C! Delete gcc and replace it by gccv, this one uses
vfork/execve as it should and works perfectly.

ixemul.library now uses the new-style inlines.

qsort() is now re-entrant and no longer uses the horrible Semaphore hack.

Moved general/fts.c to the static library. These directory-tree traversal
functions are rarely, if ever used, so they belong in libc.a and not in a
shared library.

Reorganized the Makefiles. The makefiles now use several GNU make-only
features to make them smaller and easier to maintain.  'make clean' and
'make clobber' now work correctly.  It is also no longer nessecary to add
the -srcdir option to 'sh configure' in order to create valid Makefiles.

The top level Makefile contains the line 'export CATENATE = 1'. If this
line is present, the compilation speed is greatly improved by catenating
several small C-sources together into one bigger C-source, and then the
bigger one is compiled. By commenting this line each separate source is
compiled. Note that besides improving compilation speed, the library also
gets smaller as the compiler can now determine whether a call can be made
relative or should remain absolute.

Fixed a symlink-bug (ln -s /ram/t created a symlink to /am/t, removing the
first character of the volumename).

Moved ixtrace to the new utils directory, together with the small ixrun
utility.  ixrun can be used to run Amiga batch files from /bin/sh (just put
';!ixrun' at the second line (!) of the batch file).  Also added manual
page for ixrun.

Cleaned up the static directory:  removed xmalloc.c and alloca.c as they do
not belong in the standard C library.  Also replaced the ctime.c source by
the version from elsie.nci.nih.gov, which is the official version used by
NetBSD and Linux, among others.  Finally, errlst.c and siglist.c now just
include their counterparts in the general directory.

The version information is placed in the version.in file in the
top-level directory. The version.c and version.h sources are created from
this file.

The print_base_size.c and print_user.c sources have been replaced by
create_header.c, which creates a header containing a few defines that are
used by start.s and trap.s. These used to be hard-coded, but now they are
generated, preventing future mistakes.

Added the raise function. For some reason, raise.c was never compiled into
the library. It is now.

Removed ALL sources that were not needed for compilation.

Added timezone handling. The timezone databases from elsie.nci.nih.gov are
used and installed in etc:zoneinfo. The new ixtimezone utility should be
added to the startup-sequence. This utility determines the correct offset
for Greenwich Mean Time. Read the manual page (Yes! Documentation at last!)
for more information.

Merged the ixpipe-handler into the ixemul-distribution. It has been placed
in the utils-directory.

Added hack to allow ixemul to run AmigaOS scripts without breaking them
when run from the AmigaOS shell. The problem is that the ".KEY" string
must be at the first line of the script, while ixemul also looks for "#!"
and ";!" in the first line. If a file starts with ".KEY", ixemul will now
skip the first line, before checking for "#!" and ";!".

============
VERSION 41.4
============

Integrated patches from Hans Verkuil that fix CTRL-C handling, fix another
signal bug, fix problem with "rm -f", prepare for proper timezone handling,
and remove '@' hack in argument parsing.

Applied patch from Kamil Iskra to avoid incompatibility between ixemul
and the popular KingCON 1.3.  This is KingCON's fault because it makes
invalid assumptions about the nature of reply port contained in "dp_Port"
of packets sent to it.  Also applied patch (duplicated in Hans' patches)
to crt0.c that fixes bug where the revision requester was not working
properly if the current revision is 0.

Applied patch from Rask Lambertsen (duplicated in Hans' patches) that makes
ixemul.library open "CONSOLE:" instead of "*".

Added implementation from Kriton Kyrimis for srand48, seed48, lcong48,
lrand48, nrand48, mrand48, jrand48, drand48, and erand48.

Added "#include <sys/types.h>" to <dirent.h> to be more compatible
with most current systems that do this inclusion for you.  This change
should be backwards compatible with code that does the inclusion
explicitly.  Suggested by Lars Hecking.

Changed prototype in <unistd.h> for getpgrp() to take a pid_t argument,
which matches the implementation in library/getcrap.c.  Suggested by
Lars Hecking.

Made change to <math-68881.h> in pow() so that if x<0 the code does
log(-x) rather than log(x).  Suggested by Thomas Radtke and implemented
by Lars Hecking.

Disable definitions of F_GETLK, F_SETLK, F_SETLKW, F_RDLCK, F_UNLCK, and
F_WRLCK in <fcntl.h> since they are unimplemented and thus might have misled
autoconfiguration schemes into thinking they were available.  Also fix
ixtrace.c so it will still compile without these defined.  Suggested by
Robert Ramiega.

Integrated patch from Joop van de Wege (duplicated in Hans' patches) for
setting up fpu on 68060.

============
VERSION 41.3
============

Updated DBL_MIN and DBL_MAX in float.h to include one additional digit
of precision.  Enclose negative constants in parens to avoid unexpected
conversion to subtraction via cpp macros.

Applied patch from Hans Verkuil to fix serious bug in signal handling,
to reset all signal handlers after an execve, except for those which are
being ignored (SIG_IGN).

Applied patch from Joop van de Wege to trap.s to set 68881 rounding mode
back to truncation instead of "round to nearest", as required by the
ANSI C standard which specifies truncation.

Integrated ixtrace into source tree and arranged for it to be built and
installed.

============
VERSION 41.2
============

Added "#include <sys/types.h>" to <sys/stat.h> to be more compatible
with most current systems that do this inclusion for you.  This change
should be backwards compatible with code that does the inclusion
explicitly.

Changed version string to be style guide compliant.  Also arranged that
version.o gets linked in, since it has the $VER: string and is otherwise
unreferenced by any ixemul.library code.

Merged patches from Hans Verkuil to fix execve environment passing,
always open the console for stderr if no other file handle is provided,
move AmigaOS style filename matching into glob(), and fix a small problem
with "open(NULL,...) that caused enforcer hits.

============
VERSION 41.1
============

A 68040 version of the library with soft floating point is now built,
since there are apparently systems that use the versions of the 68040
without FPUs.

Fixed crt0 files to use "jra _ENTRY" as first instruction rather than
"jmp pc@(_ENTRY)" which was getting assembled by gas 2.5.2 as a 68020+
instruction.  Note "jmp pc@(_ENTRY:W)" seems to generate the 68000
instruction but a bad jump offset.  Added corresponding change to
execve.c to recognize ixemul using executables with this change.

Fixed cpu.h, machdep.c, trap.s to avoid pc relative assembly instruction
that was getting compiled as 68020+ instruction and causing crashes on
68000 machines.

Fixed numerous files that did "#include" of "DEFS.H" rather than "defs.h".
This is an innocuous bug on the Amiga, which is case independent, but
it kills cross compilations.

============
VERSION 41.0
============

No significant changes since the 40.6 beta release other than the
mechanism (and macros) for building debug versions has been cleaned
up and the version number has been bumped to 41.0.

Did include the cat'able man pages back in the source tree, but no
work has been done yet to track down the sources for the man pages
and arrange for them to be properly integrated into the tree and
have the cat'able versions generated from those sources.

============
VERSION 40.6
============

Many bugs have been fixed since the 40.4 release, including a serious
one that was causing memory corruption and many enforcer or mungwall
hits.

Network support has been reintegrated into the library, however it is
still mostly untested.  In particular, many functions are only
available for static linking from the libnet.a library.  By the next
release, it is expected that libnet.a will be incorporated in libc.a.

Work is underway to merge the best features from at least two
different strains of the ixemul library.  Many more changes are
expected by the 41.0 release.

An environment variable called "IXSTACK" is now used to control the
stack size of programs started by system().  If the current stack is
smaller than the value in IXSTACK, the stack is raised to the value
specified in IXSTACK.  So IXSTACK is a minimum value.

Automatic stack checking, with a requestor if the stack overflows, is
available for executables compiled with a version of gcc that supports
the -mstackcheck option.  This also requires linking with new crt0 and
libc.a.

Automatic stack extension as necessary is available for executables
compiled with a version of gcc that supports the -mstackextend option.
This also requires linking with new crt0 and libc.a.