updater: check that access to mandatory externals is working

Change-Id: Ica68488f4e39c958a913936573cee67c1ff69175
Reviewed-on: https://gerrit.libreoffice.org/40754Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

bin/update/common.sh

@@ -26,6 +26,23 @@ get_file_size() {
   echo ${info[4]}
 }
 
+check_externals() {
+
+    # check whether we can call the mar executable
+    "$MAR" --version > /dev/null 2>&1
+    if [ $? != 0 ]; then
+        notice "Could not find a valid mar executable in the path or in the MAR environment variable"
+        exit 1
+    fi
+
+    # check whether we can access the bzip2 executable
+    "$BZIP2" --help > /dev/null 2>&1
+    if [ $? != 0 ]; then
+        notice "Could not find a valid bzip2 executable in the PATH or in the BZIP2 environment variable"
+        exit 1
+    fi
+}
+
 copy_perm() {
   reference="$1"
   target="$2"

bin/update/make_full_update.sh

@@ -32,6 +32,7 @@ if [ $1 = -h ]; then
   exit 1
 fi
 
+check_externals
 # -----------------------------------------------------------------------------
 
 archive="$1"