sparc/sunos:
 	under SunOs <= 4.1.2 even if the processor is a supersparc, the gcc
	option -msupersparc cannot be used in CFLAGS_MACHINE. The configure
	script omits it. 
	Thus integer multiplication and division is very slow...


sparc/solaris:
	you should be able to access as/ld/ar/ranlib maybe you should
	add /usr/ucb:/usr/ccs/bin/ ar something similar to your PATH variable


ix86/win32 with Cygwin:
	timmings system_time is always 0 and user time = real time
	buffering not implemented (after setvbuf each read returns EOF)
	Linedit does not work if CYGWIN=TTY is defined.

ix86/win32 with VC++ 6.0 and MinGW (I suppose):
	sockets not implemented
	shell/2 and system/2 do not return correct error code 
        (due to command.com bad interpreted)
        popen/3 does not work (due to command.com)
	exec/5 does not work (due to command.com)
        send_signal/2 (does not work apparently)
        select/5 only implemented with sockets (to be tested more deeply)

ix86/win32 with MinGW
	cannot be compiled with -fomit-frame-pointer (gcc 3.3.1 and 3.3.3)
	more precisely fails if engine.c compiled with -O2 -fomit-frame-pointer
	(and only these 3 functions Execute_Directive Call_Prolog Call_Next 
         suffice to fail with -O2 -fomit-frame-pointer)

ppc/linux:
	with no optimization options for gcc do not use global registers
	(use: ./configure --with-c-flags=debug --disable-regs)

ppc/darwin-macosx:
	for gcc 3.3 do not use global registers
	(use: ./configure --disable-regs)

ix86/OpenBSD:
	use gmake instead of make 

ix86/sco:
	On SCO UnixWare use --host=i586-pc-sco when using ./configure
	(until autoconf is updated to recognize UnixWare).

MacOS:
	if a Fatal Error: Segmentation Violation occurs it can be due to a C
	stack overflow. It is possible to change the size of the C stack
	before starting GNU Prolog. For instance the following command set the
	C stack size to 8Mb:

	ulimit -s 8192     (with bash)
	limit stacksize 8M (with csh) 
