update make-release-tarball.sh

latest improvements from https://github.com/meitar/git-archive-all.sh
- support for osx: use gnutar instead of tar to have support for --concatenate
- fix basename 'too many arguments' error when working directory path contains spaces

make-release-tarball.sh

@@ -103,6 +103,8 @@ OUT_FILE=$OLD_PWD # assume "this directory" without a name change by default
 SEPARATE=0
 VERBOSE=0
 
+TARCMD=tar
+[[ $(uname) == "Darwin" ]] && TARCMD=gnutar
 FORMAT=tar
 PREFIX=
 TREEISH=HEAD
@@ -177,11 +179,11 @@ fi
 if [ $VERBOSE -eq 1 ]; then
     echo -n "creating superproject archive..."
 fi
-git archive --format=$FORMAT --prefix="$PREFIX" $TREEISH > $TMPDIR/$(basename $(pwd)).$FORMAT
+git archive --format=$FORMAT --prefix="$PREFIX" $TREEISH > $TMPDIR/$(basename "$(pwd)").$FORMAT
 if [ $VERBOSE -eq 1 ]; then
     echo "done"
 fi
-echo $TMPDIR/$(basename $(pwd)).$FORMAT >| $TMPFILE # clobber on purpose
+echo $TMPDIR/$(basename "$(pwd)").$FORMAT >| $TMPFILE # clobber on purpose
 superfile=`head -n 1 $TMPFILE`
 
 if [ $VERBOSE -eq 1 ]; then
@@ -227,7 +229,7 @@ fi
 if [ $SEPARATE -eq 0 ]; then
     if [ $FORMAT == 'tar' ]; then
         sed -e '1d' $TMPFILE | while read file; do
-            tar --concatenate -f "$superfile" "$file" && rm -f "$file"
+            $TARCMD --concatenate -f "$superfile" "$file" && rm -f "$file"
         done
     elif [ $FORMAT == 'zip' ]; then
         sed -e '1d' $TMPFILE | while read file; do