Make the use64bits and usethreads friendlier/braver;

they no more wimp out if the platform is unknown.
On use64bits if gcc used -DUSE_LONG_LONG is added
to the ccflags (this dependency on gcc caused a slightly weird
reordering of Configure, but things still seem to work.)

p4raw-id: //depot/cfgperl@3841

2 files changed, 378 insertions, 391 deletions

diff --git a/Configure b/Configure
index 2030c35dde..65afbb4082 100755
--- a/Configure
+++ b/Configure
@@ -20,7 +20,7 @@
 
 # $Id: Head.U,v 3.0.1.9 1997/02/28 15:02:09 ram Exp $
 #
-# Generated on Fri Jul 30 00:08:11 EET DST 1999 [metaconfig 3.0 PL70]
+# Generated on Sun Aug  1 00:18:49 EET DST 1999 [metaconfig 3.0 PL70]
 # (with additional metaconfig patches by perlbug@perl.com)
 
 cat >/tmp/c1$$ <<EOF
@@ -2572,24 +2572,16 @@ case "$usethreads" in
 : user has specified that a threading perl is to be built,
 : we may need to set or change some other defaults.
 	if $test -f usethreads.cbu; then
+		echo "Your platform has some specific hints for threaded builds, using them..."
 		. ./usethreads.cbu
-	fi
-	case "$osname" in
-	aix|dec_osf|dos_djgpp|freebsd|hpux|irix|linux|next|openbsd|os2|solaris|vmesa)
-		# Known thread-capable platforms.
-		;;
-	*)
-	        cat >&4 <<EOM
-$osname is not known to support threads.
-Please let perlbug@perl.com know how to do that.
-
-Cannot continue, aborting.
+	else
+		$cat <<EOM
+(Your platform doesn't have any specific hints for threaded builds.
+ Assuming POSIX threads, then.)
 EOM
-		exit 1
-	;;
-    	esac # $osname
+	fi
     ;;
-esac # $usethreads
+esac
 
 cat <<EOM
 
@@ -2613,6 +2605,350 @@ esac
 set usemultiplicity
 eval $setvar 
 
+: determine where manual pages are on this system
+echo " "
+case "$sysman" in
+'') 
+	syspath='/usr/man/man1 /usr/man/mann /usr/man/manl /usr/man/local/man1'
+	syspath="$syspath /usr/man/u_man/man1 /usr/share/man/man1"
+	syspath="$syspath /usr/catman/u_man/man1 /usr/man/l_man/man1"
+	syspath="$syspath /usr/local/man/u_man/man1 /usr/local/man/l_man/man1"
+	syspath="$syspath /usr/man/man.L /local/man/man1 /usr/local/man/man1"
+	sysman=`./loc . /usr/man/man1 $syspath`
+	;;
+esac
+if $test -d "$sysman"; then
+	echo "System manual is in $sysman." >&4
+else
+	echo "Could not find manual pages in source form." >&4
+fi
+
+: see what memory models we can support
+case "$models" in
+'')
+	$cat >pdp11.c <<'EOP'
+int main() {
+#ifdef pdp11
+	exit(0);
+#else
+	exit(1);
+#endif
+}
+EOP
+	( cc -o pdp11 pdp11.c ) >/dev/null 2>&1
+	if $test -f pdp11 && ./pdp11 2>/dev/null; then
+		dflt='unsplit split'
+	else
+		tans=`./loc . X /lib/small /lib/large /usr/lib/small /usr/lib/large /lib/medium /usr/lib/medium /lib/huge`
+		case "$tans" in
+		X) dflt='none';;
+		*) if $test -d /lib/small || $test -d /usr/lib/small; then
+				dflt='small'
+			else
+				dflt=''
+			fi
+			if $test -d /lib/medium || $test -d /usr/lib/medium; then
+				dflt="$dflt medium"
+			fi
+			if $test -d /lib/large || $test -d /usr/lib/large; then
+				dflt="$dflt large"
+			fi
+			if $test -d /lib/huge || $test -d /usr/lib/huge; then
+				dflt="$dflt huge"
+			fi
+		esac
+	fi;;
+*) dflt="$models";;
+esac
+$cat <<EOM
+ 
+Some systems have different model sizes.  On most systems they are called
+small, medium, large, and huge.  On the PDP11 they are called unsplit and
+split.  If your system doesn't support different memory models, say "none".
+If you wish to force everything to one memory model, say "none" here and
+put the appropriate flags later when it asks you for other cc and ld flags.
+Venix systems may wish to put "none" and let the compiler figure things out.
+(In the following question multiple model names should be space separated.)
+
+The default for most systems is "none".
+
+EOM
+rp="Which memory models are supported?"
+. ./myread
+models="$ans"
+
+case "$models" in
+none)
+	small=''
+	medium=''
+	large=''
+	huge=''
+	unsplit=''
+	split=''
+	;;
+*split)
+	case "$split" in
+	'') if $contains '\-i' $sysman/ld.1 >/dev/null 2>&1 || \
+			 $contains '\-i' $sysman/cc.1 >/dev/null 2>&1; then
+			dflt='-i'
+		else
+			dflt='none'
+		fi;;
+	*) dflt="$split";;
+	esac
+	rp="What flag indicates separate I and D space?"
+	. ./myread
+	tans="$ans"
+	case "$tans" in
+	none) tans='';;
+	esac
+	split="$tans"
+	unsplit='';;
+*large*|*small*|*medium*|*huge*)
+	case "$models" in
+	*large*)
+		case "$large" in
+		'') dflt='-Ml';;
+		*) dflt="$large";;
+		esac
+	rp="What flag indicates large model?"
+	. ./myread
+	tans="$ans"
+	case "$tans" in
+	none) tans='';
+	esac
+	large="$tans";;
+	*) large='';;
+	esac
+	case "$models" in
+	*huge*) case "$huge" in
+		'') dflt='-Mh';;
+		*) dflt="$huge";;
+		esac
+		rp="What flag indicates huge model?"
+		. ./myread
+		tans="$ans"
+		case "$tans" in
+		none) tans='';
+		esac
+		huge="$tans";;
+	*) huge="$large";;
+	esac
+	case "$models" in
+	*medium*) case "$medium" in
+		'') dflt='-Mm';;
+		*) dflt="$medium";;
+		esac
+		rp="What flag indicates medium model?"
+		. ./myread
+		tans="$ans"
+		case "$tans" in
+		none) tans='';
+		esac
+		medium="$tans";;
+	*) medium="$large";;
+	esac
+	case "$models" in
+	*small*) case "$small" in
+		'') dflt='none';;
+		*) dflt="$small";;
+		esac
+		rp="What flag indicates small model?"
+		. ./myread
+		tans="$ans"
+		case "$tans" in
+		none) tans='';
+		esac
+		small="$tans";;
+	*) small='';;
+	esac
+	;;
+*)
+	echo "Unrecognized memory models--you may have to edit Makefile.SH" >&4
+	;;
+esac
+$rm -f pdp11.* pdp11
+
+: make some quick guesses about what we are up against
+echo " "
+$echo $n "Hmm...  $c"
+echo exit 1 >bsd
+echo exit 1 >usg
+echo exit 1 >v7
+echo exit 1 >osf1
+echo exit 1 >eunice
+echo exit 1 >xenix
+echo exit 1 >venix
+echo exit 1 >os2
+d_bsd="$undef"
+$cat /usr/include/signal.h /usr/include/sys/signal.h >foo 2>/dev/null
+if test -f /osf_boot || $contains 'OSF/1' /usr/include/ctype.h >/dev/null 2>&1
+then
+	echo "Looks kind of like an OSF/1 system, but we'll see..."
+	echo exit 0 >osf1
+elif test `echo abc | tr a-z A-Z` = Abc ; then
+	xxx=`./loc addbib blurfl $pth`
+	if $test -f $xxx; then
+	echo "Looks kind of like a USG system with BSD features, but we'll see..."
+		echo exit 0 >bsd
+		echo exit 0 >usg
+	else
+		if $contains SIGTSTP foo >/dev/null 2>&1 ; then
+			echo "Looks kind of like an extended USG system, but we'll see..."
+		else
+			echo "Looks kind of like a USG system, but we'll see..."
+		fi
+		echo exit 0 >usg
+	fi
+elif $contains SIGTSTP foo >/dev/null 2>&1 ; then
+	echo "Looks kind of like a BSD system, but we'll see..."
+	d_bsd="$define"
+	echo exit 0 >bsd
+else
+	echo "Looks kind of like a Version 7 system, but we'll see..."
+	echo exit 0 >v7
+fi
+case "$eunicefix" in
+*unixtovms*)
+	$cat <<'EOI'
+There is, however, a strange, musty smell in the air that reminds me of
+something...hmm...yes...I've got it...there's a VMS nearby, or I'm a Blit.
+EOI
+	echo exit 0 >eunice
+	d_eunice="$define"
+: it so happens the Eunice I know will not run shell scripts in Unix format
+	;;
+*)
+	echo " "
+	echo "Congratulations.  You aren't running Eunice."
+	d_eunice="$undef"
+	;;
+esac
+: Detect OS2.  The p_ variable is set above in the Head.U unit.
+case "$p_" in
+:) ;;
+*)
+	$cat <<'EOI'
+I have the feeling something is not exactly right, however...don't tell me...
+lemme think...does HAL ring a bell?...no, of course, you're only running OS/2!
+EOI
+	echo exit 0 >os2
+	;;
+esac
+if test -f /xenix; then
+	echo "Actually, this looks more like a XENIX system..."
+	echo exit 0 >xenix
+	d_xenix="$define"
+else
+	echo " "
+	echo "It's not Xenix..."
+	d_xenix="$undef"
+fi
+chmod +x xenix
+$eunicefix xenix
+if test -f /venix; then
+	echo "Actually, this looks more like a VENIX system..."
+	echo exit 0 >venix
+else
+	echo " "
+	if ./xenix; then
+		: null
+	else
+		echo "Nor is it Venix..."
+	fi
+fi
+chmod +x bsd usg v7 osf1 eunice xenix venix os2
+$eunicefix bsd usg v7 osf1 eunice xenix venix os2
+$rm -f foo
+
+: see if we need a special compiler
+echo " "
+if ./usg; then
+	case "$cc" in
+	'') case "$Mcc" in
+		/*) dflt='Mcc';;
+		*) case "$large" in
+			-M*) dflt='cc';;
+			*)	if $contains '\-M' $sysman/cc.1 >/dev/null 2>&1 ; then
+					if $contains '\-M' $sysman/cpp.1 >/dev/null 2>&1; then
+						dflt='cc'
+					else
+						dflt='cc -M'
+					fi
+				else
+					dflt='cc'
+				fi;;
+			esac;;
+		esac;;
+	*)  dflt="$cc";;
+	esac
+	case "$dflt" in
+	*M*)	$cat <<'EOM'
+On some older systems the default C compiler will not resolve multiple global
+references that happen to have the same name.  On some such systems the "Mcc"
+command may be used to force these to be resolved.  On other systems a "cc -M"
+command is required.  (Note that the -M flag on other systems indicates a
+memory model to use!) If you have the Gnu C compiler, you might wish to use
+that instead.
+
+EOM
+	;;
+	esac
+	rp="Use which C compiler?"
+	. ./myread
+	cc="$ans"
+else
+	case "$cc" in
+	'') dflt=cc;;
+	*) dflt="$cc";;
+	esac
+	rp="Use which C compiler?"
+	. ./myread
+	cc="$ans"
+fi
+: Look for a hint-file generated 'call-back-unit'.  Now that the
+: user has specified the compiler, we may need to set or change some
+: other defaults.
+if $test -f cc.cbu; then
+    . ./cc.cbu
+fi
+echo " "
+echo "Checking for GNU cc in disguise and/or its version number..." >&4
+$cat >gccvers.c <<EOM
+#include <stdio.h>
+int main() {
+#ifdef __GNUC__
+#ifdef __VERSION__
+	printf("%s\n", __VERSION__);
+#else
+	printf("%s\n", "1");
+#endif
+#endif
+	exit(0);
+}
+EOM
+if $cc -o gccvers gccvers.c; then
+	gccversion=`./gccvers`
+	case "$gccversion" in
+	'') echo "You are not using GNU cc." ;;
+	*)  echo "You are using GNU cc $gccversion." ;;
+	esac
+else
+	echo " "
+	echo "*** WHOA THERE!!! ***" >&4
+	echo "    Your C compiler \"$cc\" doesn't seem to be working!" >&4
+	case "$knowitall" in
+	'')
+	echo "    You'd better start hunting for one and let me know about it." >&4
+		exit 1
+		;;
+	esac
+fi
+$rm -f gccvers*
+case "$gccversion" in
+1*) cpp=`./loc gcc-cpp $cpp $pth` ;;
+esac
+
 cat <<EOM
 
 Perl can be built to take advantage of explicit 64-bit interfaces,
@@ -2647,22 +2983,23 @@ case "$use64bits" in
 : user has specified that a 64 bit perl is to be built,
 : we may need to set or change some other defaults.
 	if $test -f use64bits.cbu; then
+		echo "Your platform has some specific hints for 64-bit builds, using them..."
 		. ./use64bits.cbu
-	fi
-	case "$osname" in
-	aix|dec_osf|hpux|irix|solaris|unicos)
-		# Known 64-bit capable platforms.
-		;;
-	*)
-		cat >&4 <<EOM
-$osname is not known to support 64-bit interfaces.
-Please let perlbug@perl.com know how to do that.
-
-Cannot continue, aborting.
+	else
+		$cat <<EOM
+(Your platform doesn't have any specific hints for 64-bit builds.
+ This is probably okay, especially if your system is a true 64-bit system.)
 EOM
-		exit 1
-		;;
-	esac
+		case "$gccversion" in
+		'')	;;
+		*)	$cat <<EOM
+But since you seem to be using gcc,
+I will now add -DUSE_LONG_LONG to the compilation flags.
+EOM
+			ccflags="$ccflags -DUSE_LONG_LONG"
+			;;
+		esac
+	fi
 	;;
 esac
 
@@ -3290,98 +3627,6 @@ EOM
 esac
 
 
-: make some quick guesses about what we are up against
-echo " "
-$echo $n "Hmm...  $c"
-echo exit 1 >bsd
-echo exit 1 >usg
-echo exit 1 >v7
-echo exit 1 >osf1
-echo exit 1 >eunice
-echo exit 1 >xenix
-echo exit 1 >venix
-echo exit 1 >os2
-d_bsd="$undef"
-$cat /usr/include/signal.h /usr/include/sys/signal.h >foo 2>/dev/null
-if test -f /osf_boot || $contains 'OSF/1' /usr/include/ctype.h >/dev/null 2>&1
-then
-	echo "Looks kind of like an OSF/1 system, but we'll see..."
-	echo exit 0 >osf1
-elif test `echo abc | tr a-z A-Z` = Abc ; then
-	xxx=`./loc addbib blurfl $pth`
-	if $test -f $xxx; then
-	echo "Looks kind of like a USG system with BSD features, but we'll see..."
-		echo exit 0 >bsd
-		echo exit 0 >usg
-	else
-		if $contains SIGTSTP foo >/dev/null 2>&1 ; then
-			echo "Looks kind of like an extended USG system, but we'll see..."
-		else
-			echo "Looks kind of like a USG system, but we'll see..."
-		fi
-		echo exit 0 >usg
-	fi
-elif $contains SIGTSTP foo >/dev/null 2>&1 ; then
-	echo "Looks kind of like a BSD system, but we'll see..."
-	d_bsd="$define"
-	echo exit 0 >bsd
-else
-	echo "Looks kind of like a Version 7 system, but we'll see..."
-	echo exit 0 >v7
-fi
-case "$eunicefix" in
-*unixtovms*)
-	$cat <<'EOI'
-There is, however, a strange, musty smell in the air that reminds me of
-something...hmm...yes...I've got it...there's a VMS nearby, or I'm a Blit.
-EOI
-	echo exit 0 >eunice
-	d_eunice="$define"
-: it so happens the Eunice I know will not run shell scripts in Unix format
-	;;
-*)
-	echo " "
-	echo "Congratulations.  You aren't running Eunice."
-	d_eunice="$undef"
-	;;
-esac
-: Detect OS2.  The p_ variable is set above in the Head.U unit.
-case "$p_" in
-:) ;;
-*)
-	$cat <<'EOI'
-I have the feeling something is not exactly right, however...don't tell me...
-lemme think...does HAL ring a bell?...no, of course, you're only running OS/2!
-EOI
-	echo exit 0 >os2
-	;;
-esac
-if test -f /xenix; then
-	echo "Actually, this looks more like a XENIX system..."
-	echo exit 0 >xenix
-	d_xenix="$define"
-else
-	echo " "
-	echo "It's not Xenix..."
-	d_xenix="$undef"
-fi
-chmod +x xenix
-$eunicefix xenix
-if test -f /venix; then
-	echo "Actually, this looks more like a VENIX system..."
-	echo exit 0 >venix
-else
-	echo " "
-	if ./xenix; then
-		: null
-	else
-		echo "Nor is it Venix..."
-	fi
-fi
-chmod +x bsd usg v7 osf1 eunice xenix venix os2
-$eunicefix bsd usg v7 osf1 eunice xenix venix os2
-$rm -f foo
-
 : see if setuid scripts can be secure
 $cat <<EOM
 
@@ -3492,258 +3737,6 @@ esac
 set d_dosuid
 eval $setvar
 
-: determine where manual pages are on this system
-echo " "
-case "$sysman" in
-'') 
-	syspath='/usr/man/man1 /usr/man/mann /usr/man/manl /usr/man/local/man1'
-	syspath="$syspath /usr/man/u_man/man1 /usr/share/man/man1"
-	syspath="$syspath /usr/catman/u_man/man1 /usr/man/l_man/man1"
-	syspath="$syspath /usr/local/man/u_man/man1 /usr/local/man/l_man/man1"
-	syspath="$syspath /usr/man/man.L /local/man/man1 /usr/local/man/man1"
-	sysman=`./loc . /usr/man/man1 $syspath`
-	;;
-esac
-if $test -d "$sysman"; then
-	echo "System manual is in $sysman." >&4
-else
-	echo "Could not find manual pages in source form." >&4
-fi
-
-: see what memory models we can support
-case "$models" in
-'')
-	$cat >pdp11.c <<'EOP'
-int main() {
-#ifdef pdp11
-	exit(0);
-#else
-	exit(1);
-#endif
-}
-EOP
-	( cc -o pdp11 pdp11.c ) >/dev/null 2>&1
-	if $test -f pdp11 && ./pdp11 2>/dev/null; then
-		dflt='unsplit split'
-	else
-		tans=`./loc . X /lib/small /lib/large /usr/lib/small /usr/lib/large /lib/medium /usr/lib/medium /lib/huge`
-		case "$tans" in
-		X) dflt='none';;
-		*) if $test -d /lib/small || $test -d /usr/lib/small; then
-				dflt='small'
-			else
-				dflt=''
-			fi
-			if $test -d /lib/medium || $test -d /usr/lib/medium; then
-				dflt="$dflt medium"
-			fi
-			if $test -d /lib/large || $test -d /usr/lib/large; then
-				dflt="$dflt large"
-			fi
-			if $test -d /lib/huge || $test -d /usr/lib/huge; then
-				dflt="$dflt huge"
-			fi
-		esac
-	fi;;
-*) dflt="$models";;
-esac
-$cat <<EOM
- 
-Some systems have different model sizes.  On most systems they are called
-small, medium, large, and huge.  On the PDP11 they are called unsplit and
-split.  If your system doesn't support different memory models, say "none".
-If you wish to force everything to one memory model, say "none" here and
-put the appropriate flags later when it asks you for other cc and ld flags.
-Venix systems may wish to put "none" and let the compiler figure things out.
-(In the following question multiple model names should be space separated.)
-
-The default for most systems is "none".
-
-EOM
-rp="Which memory models are supported?"
-. ./myread
-models="$ans"
-
-case "$models" in
-none)
-	small=''
-	medium=''
-	large=''
-	huge=''
-	unsplit=''
-	split=''
-	;;
-*split)
-	case "$split" in
-	'') if $contains '\-i' $sysman/ld.1 >/dev/null 2>&1 || \
-			 $contains '\-i' $sysman/cc.1 >/dev/null 2>&1; then
-			dflt='-i'
-		else
-			dflt='none'
-		fi;;
-	*) dflt="$split";;
-	esac
-	rp="What flag indicates separate I and D space?"
-	. ./myread
-	tans="$ans"
-	case "$tans" in
-	none) tans='';;
-	esac
-	split="$tans"
-	unsplit='';;
-*large*|*small*|*medium*|*huge*)
-	case "$models" in
-	*large*)
-		case "$large" in
-		'') dflt='-Ml';;
-		*) dflt="$large";;
-		esac
-	rp="What flag indicates large model?"
-	. ./myread
-	tans="$ans"
-	case "$tans" in
-	none) tans='';
-	esac
-	large="$tans";;
-	*) large='';;
-	esac
-	case "$models" in
-	*huge*) case "$huge" in
-		'') dflt='-Mh';;
-		*) dflt="$huge";;
-		esac
-		rp="What flag indicates huge model?"
-		. ./myread
-		tans="$ans"
-		case "$tans" in
-		none) tans='';
-		esac
-		huge="$tans";;
-	*) huge="$large";;
-	esac
-	case "$models" in
-	*medium*) case "$medium" in
-		'') dflt='-Mm';;
-		*) dflt="$medium";;
-		esac
-		rp="What flag indicates medium model?"
-		. ./myread
-		tans="$ans"
-		case "$tans" in
-		none) tans='';
-		esac
-		medium="$tans";;
-	*) medium="$large";;
-	esac
-	case "$models" in
-	*small*) case "$small" in
-		'') dflt='none';;
-		*) dflt="$small";;
-		esac
-		rp="What flag indicates small model?"
-		. ./myread
-		tans="$ans"
-		case "$tans" in
-		none) tans='';
-		esac
-		small="$tans";;
-	*) small='';;
-	esac
-	;;
-*)
-	echo "Unrecognized memory models--you may have to edit Makefile.SH" >&4
-	;;
-esac
-$rm -f pdp11.* pdp11
-
-: see if we need a special compiler
-echo " "
-if ./usg; then
-	case "$cc" in
-	'') case "$Mcc" in
-		/*) dflt='Mcc';;
-		*) case "$large" in
-			-M*) dflt='cc';;
-			*)	if $contains '\-M' $sysman/cc.1 >/dev/null 2>&1 ; then
-					if $contains '\-M' $sysman/cpp.1 >/dev/null 2>&1; then
-						dflt='cc'
-					else
-						dflt='cc -M'
-					fi
-				else
-					dflt='cc'
-				fi;;
-			esac;;
-		esac;;
-	*)  dflt="$cc";;
-	esac
-	case "$dflt" in
-	*M*)	$cat <<'EOM'
-On some older systems the default C compiler will not resolve multiple global
-references that happen to have the same name.  On some such systems the "Mcc"
-command may be used to force these to be resolved.  On other systems a "cc -M"
-command is required.  (Note that the -M flag on other systems indicates a
-memory model to use!) If you have the Gnu C compiler, you might wish to use
-that instead.
-
-EOM
-	;;
-	esac
-	rp="Use which C compiler?"
-	. ./myread
-	cc="$ans"
-else
-	case "$cc" in
-	'') dflt=cc;;
-	*) dflt="$cc";;
-	esac
-	rp="Use which C compiler?"
-	. ./myread
-	cc="$ans"
-fi
-: Look for a hint-file generated 'call-back-unit'.  Now that the
-: user has specified the compiler, we may need to set or change some
-: other defaults.
-if $test -f cc.cbu; then
-    . ./cc.cbu
-fi
-echo " "
-echo "Checking for GNU cc in disguise and/or its version number..." >&4
-$cat >gccvers.c <<EOM
-#include <stdio.h>
-int main() {
-#ifdef __GNUC__
-#ifdef __VERSION__
-	printf("%s\n", __VERSION__);
-#else
-	printf("%s\n", "1");
-#endif
-#endif
-	exit(0);
-}
-EOM
-if $cc -o gccvers gccvers.c; then
-	gccversion=`./gccvers`
-	case "$gccversion" in
-	'') echo "You are not using GNU cc." ;;
-	*)  echo "You are using GNU cc $gccversion." ;;
-	esac
-else
-	echo " "
-	echo "*** WHOA THERE!!! ***" >&4
-	echo "    Your C compiler \"$cc\" doesn't seem to be working!" >&4
-	case "$knowitall" in
-	'')
-	echo "    You'd better start hunting for one and let me know about it." >&4
-		exit 1
-		;;
-	esac
-fi
-$rm -f gccvers*
-case "$gccversion" in
-1*) cpp=`./loc gcc-cpp $cpp $pth` ;;
-esac
-
 : What should the include directory be ?
 echo " "
 $echo $n "Hmm...  $c"
diff --git a/README.threads b/README.threads
index 4ae2f37ae5..b02e607d2b 100644
--- a/README.threads
+++ b/README.threads
@@ -55,27 +55,21 @@ you believe supports POSIX.1c threads then read on.  Additional
 information may be in a platform-specific "hints" file in the hints/
 subdirectory.
 
-First of all, because threads are such an experimentral feature
-there's a failsafe in Configure that stops unknown platforms
-from using threads.  Search for "is not known to support threads". 
-About five lines above that is a line that has a list of operating
-system names separated with |-signs.  Append your operating system
-(perl -le 'print $^O') to that list.
-
-On other platforms that use Configure to build perl, omit the -d
-from your ./Configure arguments. For example, use:
+On platforms that use Configure to build perl, omit the -d from your
+./Configure arguments. For example, use:
 
     ./Configure -Dusethreads
 
 When Configure prompts you for ccflags, insert any other arguments in
-there that your compiler needs to use POSIX threads. When Configure
-prompts you for linking flags, include any flags required for
-threading (usually nothing special is required here).  Finally, when
-Configure prompts you for libraries, include any necessary libraries
-(e.g. -lpthread).  Pay attention to the order of libraries.  It is
-probably necessary to specify your threading library *before* your
-standard C library, e.g.  it might be necessary to have -lpthread -lc,
-instead of -lc -lpthread.  You may also need to use -lc_r instead
+there that your compiler needs to use POSIX threads (-D_REENTRANT,
+-pthreads, -threads, -pthread, -thread, are good guesses). When
+Configure prompts you for linking flags, include any flags required
+for threading (usually nothing special is required here).  Finally,
+when Configure prompts you for libraries, include any necessary
+libraries (e.g. -lpthread).  Pay attention to the order of libraries.
+It is probably necessary to specify your threading library *before*
+your standard C library, e.g.  it might be necessary to have -lpthread
+-lc, instead of -lc -lpthread.  You may also need to use -lc_r instead
 of -lc.
 
 Once you have specified all your compiler flags, you can have Configure