release script: account for newer warnings.

* Recent versions of shellcheck added some checks not yet
  passed by the code.

scripts/release/check-gitignore

@@ -43,6 +43,8 @@
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 set -e
+# trap functions are incorrectly diagnosed by shellcheck as unreachable
+# shellcheck disable=SC2317
 errMsg()
 {
   typeset cmd=$BASH_COMMAND pfx
@@ -58,7 +60,7 @@ trap errMsg ERR
 
 # shellcheck source=get-package-and-version.shinc
 . scripts/release/get-package-and-version.shinc
-if [[ x${TMPDIR+set} = x ]]; then
+if [[ ${TMPDIR+set} = '' ]]; then
   if [[ -d "$XDG_RUNTIME_DIR" && -w "$XDG_RUNTIME_DIR" ]]; then
     TMPDIR=$XDG_RUNTIME_DIR
   elif [[ -d /dev/shm && -w /dev/shm ]]; then
@@ -99,7 +101,7 @@ if command -v rsync >/dev/null ; then
 else
   cp -a "$repo"/. .
 fi
-bash -x $reconfCmd >&6 2>&6
+bash -x "$reconfCmd" >&6 2>&6
 set +e
 git update-index -q --ignore-submodules --refresh
 set -e

scripts/release/make-distcheck

@@ -48,7 +48,7 @@ if (( ${DEBUG:-0} )); then
 else
   MAKE_DEBUG_ARGS=()
 fi
-if [[ x${TMPDIR+set} = x ]]; then
+if [[ ${TMPDIR+set} = '' ]]; then
   if [[ -d /dev/shm && -w /dev/shm ]]; then
     TMPDIR=/dev/shm
   else

scripts/release/make-release-commit

@@ -118,7 +118,7 @@ lalibs=()
 while read -r libline ; do
   echo "inspecting $libline" >&2
   libpath=${libline%%/Makefile.am:*}
-  las=${libline##${libpath}/Makefile.am:}
+  las=${libline##"${libpath}"/Makefile.am:}
   for la in ${las} ; do
     lalibdirs+=("${libpath}")
     lalibs+=("${la/.la/_la}")