[PATCH 2/8] Do not use shell's old-style command substitution

To quote the BashFAQ[0]:
Why is $(...) preferred over `...` (backticks)?

The `cmd` backtick format is the legacy syntax for command substitution,
required only by more than 30-year-old Bourne shells. ...

[0]: http://mywiki.wooledge.org/BashFAQ/082
---
 check_sec.sh          |  4 ++--
 contrib/iconv/make.sh |  2 +-
 mkchangelog.sh        |  2 +-
 mkreldate.sh          |  4 ++--
 version.sh            | 10 +++++-----
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/check_sec.sh b/check_sec.sh
index 179ac1ff..03bf2188 100755
--- a/check_sec.sh
+++ b/check_sec.sh
@@ -4,7 +4,7 @@
 # grep for some things which may look like security problems.
 #
 
-TMPFILE=`mktemp check_sec.tmp.XXXXXX` || exit 1
+TMPFILE=$(mktemp check_sec.tmp.XXXXXX) || exit 1
 
 RV=0;
 
@@ -27,7 +27,7 @@ do_check_files ()
 
 do_check ()
 {
-        do_check_files "$1" "$2" "$3" `find . -name '*.c' -print`
+        do_check_files "$1" "$2" "$3" $(find . -name '*.c' -print)
 }
 
 do_check '\<fopen.*'\"'.*w' __FOPEN_CHECKED__ "Alert: Unchecked fopen calls."
diff --git a/contrib/iconv/make.sh b/contrib/iconv/make.sh
index 1db621e6..1382b151 100755
--- a/contrib/iconv/make.sh
+++ b/contrib/iconv/make.sh
@@ -21,6 +21,6 @@ for f in $LIBICONV/libcharset/tools/* ; do
 		sed '1,/^$/d' $f | awk '($4 != $3) { printf ("iconv-hook %s %s\n", $4, $3); }' | \
 			sed -e 's/^iconv-hook SJIS /iconv-hook Shift_JIS /gi' |
 			sort -u > tmp.rc )
-	test -s tmp.rc && mv tmp.rc iconv.`basename $f`.rc
+	test -s tmp.rc && mv tmp.rc iconv.$(basename $f).rc
 	rm -f tmp.rc
 done
diff --git a/mkchangelog.sh b/mkchangelog.sh
index 8a257023..9f551012 100755
--- a/mkchangelog.sh
+++ b/mkchangelog.sh
@@ -5,7 +5,7 @@
 # This would generate based on the last update of the ChangeLog, instead:
 # lrev=$(git log -1 --pretty=format:"%H" ChangeLog)
 
-lrev=`git describe --tags --match 'mutt-*-rel' --abbrev=0`
+lrev=$(git describe --tags --match 'mutt-*-rel' --abbrev=0)
 
 # This is a rough approximation of the official ChangeLog format
 # previously generated by hg.  Git doesn't provide enough formatting
diff --git a/mkreldate.sh b/mkreldate.sh
index 927967d5..b9be6373 100755
--- a/mkreldate.sh
+++ b/mkreldate.sh
@@ -3,9 +3,9 @@
 # Generates the reldate.h contents from either git or the ChangeLog file
 
 if [ -r ".git" ] && command -v git >/dev/null 2>&1; then
-  reldate=`TZ=UTC git log -1 --date=format-local:"%F" --pretty=format:"%cd"`
+  reldate=$(TZ=UTC git log -1 --date=format-local:"%F" --pretty=format:"%cd")
 else
-  reldate=`head -n 1 ChangeLog | LC_ALL=C cut -d ' ' -f 1`
+  reldate=$(head -n 1 ChangeLog | LC_ALL=C cut -d ' ' -f 1)
 fi
 
 echo $reldate
diff --git a/version.sh b/version.sh
index 6d87b31f..6abdcc0c 100644
--- a/version.sh
+++ b/version.sh
@@ -3,17 +3,17 @@
 # Switch to directory where this script lives so that further commands are run
 # from the root directory of the source.  The script path and srcdir are double
 # quoted to allow the space character to appear in the path.
-srcdir=`dirname "$0"` && cd "$srcdir" || exit 1
+srcdir=$(dirname "$0") && cd "$srcdir" || exit 1
 
 # Ensure that we have a repo here.
 # If not, just cat the VERSION file; it contains the latest release number.
 { [ -r ".git" ] && command -v git >/dev/null 2>&1; } \
 || exec cat VERSION
 
-latesttag=`git describe --tags --match 'mutt-*-rel' --abbrev=0`
-version=`echo $latesttag | sed -e s/mutt-// -e s/-rel// -e s/-/./g`
-distance=`git rev-list --count $latesttag..`
-commitid=`git rev-parse --short HEAD`
+latesttag=$(git describe --tags --match 'mutt-*-rel' --abbrev=0)
+version=$(echo "$latesttag" | sed -e s/mutt-// -e s/-rel// -e s/-/./g)
+distance=$(git rev-list --count "$latesttag"..)
+commitid=$(git rev-parse --short HEAD)
 
 [ x = "x$distance" ] && exec cat VERSION
 
-- 
2.51.0