Add --no-as-needed, --export-dynamic

This makes dynamic libraries work on Linux arm64! Thanks to Lukáš
Zaoral at Red Hat for finding the key to the fix, which is passing
--no-as-needed to the linker on Linux to avoid glibc interfering
with libast in identically named functions like AST regcomp(3).
Linux systems vary as to whether --as-needed is on by default.

src/cmd/INIT/make.probe:
- Add probe for the --as-needed and --no-as-needed linker options.
  Thanks to Johnothan King.

**/Mamfile:
- Use the --no-as-needed probe result (either -Wl,-no-as-needed or
  empty) from ${mam_cc_LD_NOASNEEDED} whenever linking anything;
  add it to LDFLAGS before invoking dylink.
- ksh and shcomp also need the results of the existing
  --export-dynamic probe; this option is needed on Linux as without
  it ksh fails to export symbols to loadable builtins. See:
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=821806
  Thanks to Johnothan King, again.

src/cmd/INIT/mamprobe.sh:
- Update version number. This change causes mamake to redo the
  probe (it checks for a change in mamprobe but not in make.probe;
  I should probably fix that at some point). We need mamake to redo
  the probe for the --no-as-needed addition to take effect.

src/lib/libast/comp/errno.c:
- Make one trivial change (copyright year) to force libast to
  relink -- which then triggers a relink of everything else.

src/cmd/INIT/dylink.sh:
- Remove crash warning for Linux arm. :-)

Co-authored-by: Johnothan King <johnothanking@protonmail.com>
Co-authored-by: Lukáš Zaoral <lzaoral@redhat.com>

src/cmd/INIT/dylink.sh

@@ -85,14 +85,6 @@ ms)	case $suffix in
 esac
 
 case $HOSTTYPE in
-linux.aarch* | linux.arm*)
-	case ${AST_CRASH_ME:+s} in
-	'')	note	"ksh with dynamic libraries is known to crash on $HOSTTYPE." \
-			"The cause is still a mystery to us. Please help us debug it at:" \
-			"https://github.com/ksh93/ksh/issues/TODO" \
-			"Skipping. Export AST_CRASH_ME to build dynamic libraries."
-		exit 0 ;;  # continue build
-	esac ;;
 cygwin.*)
 	note "Dynamic libraries are not supported on $HOSTTYPE."
 	exit 0 ;;  # continue build

src/cmd/INIT/make.probe

@@ -3,7 +3,7 @@
 # Glenn Fowler
 # AT&T Research
 #
-# @(#)make.probe (ksh 93u+m) 2024-01-09
+# @(#)make.probe (ksh 93u+m) 2024-03-05
 #
 # C probe for make
 #
@@ -21,6 +21,7 @@ probe_export_dynamic="-rdynamic -export-dynamic -Wl,-export-dynamic -Wl,-E -bexp
 probe_gcc_optimize="-Os"
 probe_gcc_version="*[Gg][Cc][Cc]*"
 probe_include_local="'-ignore-source-dir -iquote' -iquote -I-"
+probe_ldasneeded="-Wl,-as-needed -Wl,-no-as-needed"
 probe_ldlazy='-zlazyload -znolazyload -Wl,-zlazyload -Wl,-znolazyload'
 probe_ldlib="LD_LIBRARY_PATH LIBPATH LPATH"
 probe_ldmap="'-Wl,-M' '-Qoption ld -M' '-Wl,-m' '-m'"
@@ -129,6 +130,7 @@ export_dynamic=
 gnu=
 implicitc=
 include_local=
+ldasneeded=
 lddynamic=
 ldlazy=
 ldnolazy=
@@ -557,6 +559,20 @@ then	eval set x x $probe_ldlazy
 		ldnorecord=$2
 		break
 	done
+	eval set x x $probe_ldasneeded
+	while	:
+	do	shift
+		shift
+		case $# in
+		0)	break ;;
+		esac
+		rm -f strip.$exe
+		$cc -o strip.$exe $1 strip.$obj $2 2>f && test -f strip.$exe || continue
+		cmp -s e f || continue
+		ldasneeded=$1
+		ldnoasneeded=$2
+		break
+	done
 fi
 
 case $cc_dll:$cc_pic:$so:$dynamic:$static in
@@ -1941,6 +1957,8 @@ CC_DYNAMIC=$dynamic
 CC_EXPORT_DYNAMIC=$export_dynamic
 CC_INCLUDE_LOCAL=$include_local
 CC_LD=$ld
+CC_LD_ASNEEDED=$ldasneeded
+CC_LD_NOASNEEDED=$ldnoasneeded
 CC_LD_DYNAMIC=$lddynamic
 CC_LD_LAZY=$ldlazy
 CC_LD_NOLAZY=$ldnolazy
@@ -2045,6 +2063,8 @@ $CC_CC)	echo if LDSHARED
 *)	echo CC.LD = $CC_LD
 	;;
 esac
+echo CC.LD.ASNEEDED = $CC_LD_ASNEEDED
+echo CC.LD.NOASNEEDED = $CC_LD_NOASNEEDED
 echo CC.LD.DYNAMIC = $CC_LD_DYNAMIC
 echo CC.LD.LAZY = $CC_LD_LAZY
 echo CC.LD.NOLAZY = $CC_LD_NOLAZY

src/cmd/INIT/mamprobe.sh

@@ -37,7 +37,7 @@ opt=
 case `(getopts '[-][123:xyz]' opt --xyz; echo 0$opt) 2>/dev/null` in
 0123)	USAGE=$'
 [-?
-@(#)$Id: mamprobe (ksh 93u+m) 2024-02-10 $
+@(#)$Id: mamprobe (ksh 93u+m) 2024-03-05 $
 ]
 [+NAME?mamprobe - generate MAM cc probe info]
 [+DESCRIPTION?\bmamprobe\b generates MAM (make abstract machine) \bcc\b(1)

src/cmd/builtin/Mamfile

@@ -145,6 +145,7 @@ make install virtual
 	make ${INSTALLROOT}/dyn/bin/pty dontcare
 		prev pty
 		prev ${INSTALLROOT}/lib/lib/cmd
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED}"
 		exec - dylink -e pty ${mam_libutil} $(cat ${INSTALLROOT}/lib/lib/cmd) pty.o
 	done
 

src/cmd/ksh93/Mamfile

@@ -1242,18 +1242,21 @@ make install virtual
 	make ${INSTALLROOT}/dyn/lib/libshell${DYLIB_SUFFIX} dontcare
 		prev libshell.a
 		prev shell.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED}"
 		exec - dylink -m shell -s ${DYLIB_SUFFIX} $(sed 1d shell.req) ${_libshell_object_files_}
 	done
 
 	make ${INSTALLROOT}/dyn/bin/ksh dontcare
 		prev ksh
 		prev shell.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED} ${mam_cc_EXPORT_DYNAMIC}"
 		exec - dylink -e ksh $(cat shell.req) ${mam_libnsl} ${mam_libm} pmain.o
 	done
 
 	make ${INSTALLROOT}/dyn/bin/shcomp dontcare
 		prev shcomp
 		prev shell.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED} ${mam_cc_EXPORT_DYNAMIC}"
 		exec - dylink -e shcomp $(cat shell.req) ${mam_libnsl} ${mam_libm} shcomp.o
 	done
 

src/cmd/ksh93/tests/exit.sh

@@ -2,7 +2,7 @@
 #                                                                      #
 #               This software is part of the ast package               #
 #          Copyright (c) 1982-2011 AT&T Intellectual Property          #
-#          Copyright (c) 2020-2023 Contributors to ksh 93u+m           #
+#          Copyright (c) 2020-2024 Contributors to ksh 93u+m           #
 #                      and is licensed under the                       #
 #                 Eclipse Public License, Version 2.0                  #
 #                                                                      #

src/lib/libast/Mamfile

@@ -4956,6 +4956,7 @@ make install virtual
 	make ${INSTALLROOT}/dyn/lib/libast${DYLIB_SUFFIX} dontcare
 		prev libast.a
 		prev ast.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED}"
 		exec - dylink -m ast -s ${DYLIB_SUFFIX} $(sed 1d ast.req) ${_libast_object_files_}
 	done
 

src/lib/libast/comp/errno.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1985-2011 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2022 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2024 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 2.0                  *
 *                                                                      *

src/lib/libcmd/Mamfile

@@ -488,6 +488,7 @@ make install virtual
 	make ${INSTALLROOT}/dyn/lib/libcmd${DYLIB_SUFFIX} dontcare
 		prev libcmd.a
 		prev cmd.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED}"
 		exec - dylink -m cmd -s ${DYLIB_SUFFIX} $(sed 1d cmd.req) ${_libcmd_object_files_}
 	done
 

src/lib/libdll/Mamfile

@@ -197,6 +197,7 @@ make install virtual
 	make ${INSTALLROOT}/dyn/lib/libdll${DYLIB_SUFFIX} dontcare
 		prev libdll.a
 		prev dll.req
+		exec - export LDFLAGS="$LDFLAGS ${mam_cc_LD_NOASNEEDED}"
 		exec - dylink -m dll -s ${DYLIB_SUFFIX} $(sed 1d dll.req) ${_libdll_object_files_}
 	done