CONFIGURE: Remove bashism
    
    There were errors in configure script when /bin/sh was not bash
    ./configure: 15889: test: xfedora: unexpected operator
    ./configure: 19981: test: xyes: unexpected operator
    ./configure: 23103: test: x1: unexpected operator
    
    The equality operator "==" works in bash but it's not a standard.
    The man page test(1) also does not mention it.
    There is only short version "="
    
           STRING1 = STRING2
                  the strings are equal