Added mutex lock to log output.

compile

@@ -5,7 +5,7 @@ do
    filename="${file%.*}"
    list="$list $filename.o"  
    echo -n "Compiling $filename..."
-   g++ -c $file &
+   g++ -g -c $file 
    if [ $? = '0' ]
    then
     echo "OK"