Use older shell constructs to fix PR47382

The Solaris 10 /bin/sh does not support POSIX command or arithmetic
substitutions.  This commit reverts to using the old style backtick
form and the expr command for arithmetic.

ChangeLog

@@ -1,3 +1,20 @@
+2021-03-25  Jacob Bachmeyer  <jcb@gnu.org>
+
+	PR47382
+
+	* dejagnu, runtest: Remove use of "$()" command substitution and
+	"$(())" arithmetic substitution shell constructs.  The /bin/sh on
+	Solaris 10 does not support them.  They were replaced with the
+	traditional backticks for command substitution and backticks and
+	the expr command for arithmetic substitution.
+
+	Also add markers to explicitly disable shellcheck warnings that
+	would lead to reintroducing these problems.
+
+	Also avoid the non-portable "`..."..."...`" construct on a warning
+	in the GNU Autoconf manual, section "Shell Substitutions",
+	although this introduces additional variables.
+
 2021-03-22  Jacob Bachmeyer  <jcb@gnu.org>
 
 	* configure: Regenerate.

dejagnu

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (C) 2018 Free Software Foundation, Inc.
+# Copyright (C) 2018, 2021 Free Software Foundation, Inc.
 #
 # This file is part of DejaGnu.
 #
@@ -28,6 +28,18 @@
 # either be run with a command name as the first (few) argument(s), via a
 # link from the command name, or some combination of those.
 
+# shellcheck disable=SC2003
+# The shellcheck tool complains about use of expr and recommends using
+# newer shell features instead.  Solaris 10 /bin/sh does not support the
+# newer features, so we must use expr in this script.
+
+# shellcheck disable=SC2006
+# The shellcheck tool complains about the old style backtick command
+# substitution.  Solaris 10 /bin/sh does not support the new style $()
+# command substitution and the usage of command substitution in this script
+# is simple enough to work.  Most notably, nesting backtick command
+# substitution is tricky, but we do not do that.
+
 # shellcheck disable=SC2209
 # The shellcheck tool complains about assigning certain constant strings to
 # variables.  In this script, the intended meaning is obvious in context.
@@ -58,18 +70,18 @@ verbose=0
 for a in "$@"; do
     case $a in
 	--help)				want_help=true			;;
-	-v|--v|-verbose|--verbose)	verbose=$((verbose + 1)) ;;
+	-v|--v|-verbose|--verbose)	verbose=`expr $verbose + 1`	;;
 	-V|--V|-version|--version)	want_version=true		;;
     esac
 done
 
 if expr "$verbose" \> 0 > /dev/null ; then
-    echo Verbose level is $verbose
+    echo Verbose level is "$verbose"
 fi
 
 ## Get the file name of this script and deduce @bindir@.
 
-bindir="$(echo "$0" | sed -e 's@/[^/]*$@@')"
+bindir=`echo "$0" | sed -e 's@/[^/]*$@@'`
 if expr "$verbose" \> 0 > /dev/null ; then
     echo Running launcher from "$bindir"
 fi
@@ -97,9 +109,10 @@ elif test -d "${bindir}/commands" && test -f "${bindir}/runtest.exp" ; then
     datadir="${bindir}"
 else
     commdir=
+    bindir1up_check=`echo "$bindir" | sed -e 's@/[^/]*$@/share/dejagnu@'`
+    bindir2up_check=`echo "$bindir" | sed -e 's@/[^/]*/[^/]*$@/share/dejagnu@'`
     for i in \
-	"$(echo "$bindir" | sed -e 's@/[^/]*$@/share/dejagnu@')" \
-	"$(echo "$bindir" | sed -e 's@/[^/]*/[^/]*$@/share/dejagnu@')" \
+	"${bindir1up_check}" "${bindir2up_check}" \
 	/usr/share/dejagnu /usr/local/share/dejagnu
     do
 	if expr "$verbose" \> 1 > /dev/null ; then
@@ -126,14 +139,14 @@ fi
 
 # Are we just looking for version information?
 if $want_version ; then
-    frame_version=$(grep '^set frame_version' "${datadir}/runtest.exp" \
-	| sed 's/^[^0-9]*//')
+    frame_version=`grep '^set frame_version' "${datadir}/runtest.exp" \
+	| sed 's/^[^0-9]*//'`
     echo 'dejagnu auxiliary launcher (DejaGnu)' "$frame_version"
     exit 0
 fi
 
 # Remove any leading autoconf platform prefix and the "dejagnu" prefix.
-command="$(basename "$0" | sed -e 's/^.*-\?dejagnu-\?//')"
+command=`basename "$0" | sed -e 's/^.*-\?dejagnu-\?//'`
 
 while expr $# \> 0 > /dev/null
 do
@@ -401,8 +414,8 @@ if $want_help ; then
 	echo ERROR: file "'$help_file'" does not contain a help message
 	exit 2
     fi
-    help_prefix_pat=$(grep '#help' "$help_file" \
-	| sed -e 's/#help.*$//' -e '1q' | tr '[:print:][:blank:]' .)
+    help_prefix_pat=`grep '#help' "$help_file" \
+	| sed -e 's/#help.*$//' -e '1q' | tr '[:print:][:blank:]' .`
     if expr "$verbose" \> 1 > /dev/null ; then
 	echo Extracting help from "'$help_file'" with prefix "'$help_prefix_pat'"
     fi

runtest

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (C) 1992-2016 Free Software Foundation, Inc.
+# Copyright (C) 1992-2016, 2021 Free Software Foundation, Inc.
 #
 # This file is part of DejaGnu.
 #
@@ -21,6 +21,18 @@
 # This script was written by Rob Savoye. The script finds the proper
 # expect shell and then starts DejaGnu.
 
+# shellcheck disable=SC2003
+# The shellcheck tool complains about use of expr and recommends using
+# newer shell features instead.  Solaris 10 /bin/sh does not support the
+# newer features, so we must use expr in this script.
+
+# shellcheck disable=SC2006
+# The shellcheck tool complains about the old style backtick command
+# substitution.  Solaris 10 /bin/sh does not support the new style $()
+# command substitution and the usage of command substitution in this script
+# is simple enough to work.  Most notably, nesting backtick command
+# substitution is tricky, but we do not do that.
+
 # Get the execution path to this script and the current directory.
 
 mypath=${0-.}
@@ -40,13 +52,13 @@ else
     done
     IFS="$save_ifs"
 fi
-execpath=$(echo "$mypath" | sed -e 's@/[^/]*$@@')
+execpath=`echo "$mypath" | sed -e 's@/[^/]*$@@'`
 
 # Get the name by which runtest was invoked and extract the config
 # triplet.
 
-runtest=$(echo "$mypath" | sed -e 's@^.*/@@')
-target=$(echo "$runtest" | sed -e 's/-runtest$//')
+runtest=`echo "$mypath" | sed -e 's@^.*/@@'`
+target=`echo "$runtest" | sed -e 's/-runtest$//'`
 if [ "$target" != runtest ] ; then
     target="--target ${target}"
 else
@@ -86,7 +98,7 @@ verbose=0
 debug=""
 for a in "$@" ; do
   case $a in
-      -v|--v|-verb*|--verb*)    verbose=$((verbose + 1)) ;;
+      -v|--v|-verb*|--verb*)    verbose=`expr $verbose + 1` ;;
       -D0|--D0)       debug="-D 0" ;;
       -D1|--D1)       debug="-D 1" ;;
   esac
@@ -108,10 +120,11 @@ fi
 #
 # .. which is a very weak assumption
 
+bindir1up_check=`echo "$execpath" | sed -e 's@/[^/]*$@/share/dejagnu@'`
+bindir2up_check=`echo "$execpath" | sed -e 's@/[^/]*/[^/]*$@/share/dejagnu@'`
+
 for i in \
-    $(echo "$execpath" | sed  -e 's@/[^/]*$@/share/dejagnu@') \
-    $(echo "$execpath" | sed  -e 's@/[^/]*/[^/]*$@/share/dejagnu@') \
-    "$execpath" \
+    "${bindir1up_check}" "${bindir2up_check}" "$execpath" \
     /usr/share/dejagnu \
     /usr/local/share/dejagnu ; do
     if expr "$verbose" \> 1 > /dev/null ; then
@@ -144,4 +157,7 @@ if ! command -v "$expectbin" > /dev/null ; then
     exit 1
 fi
 
+# The `debug' and `target' variables are _intended_ to contain zero or two
+# words each.  Word splitting is desired here.
+# shellcheck disable=SC2086
 exec "$expectbin" $debug -- "$runpath"/runtest.exp $target ${1+"$@"}