The syntax that allows specifying multiple variants in one CLI argument has the following downsides:

1. It doesn't solve any real problem. The same configuration can be expressed using one variant per argument.
2. The resulting syntax is ambiguous. What does +openssl=/usr-mysql mean? Is -mysql part of the openssl prefix or it disables the mysql variant?

   var_dump(
       VariantParser::parseCommandArguments(array('+openssl=/usr-mysql'))
   );
   /*
   array(3) {
     'enabled_variants' =>
     array(1) {
       'openssl' =>
       string(10) "/usr-mysql"
     }
     'disabled_variants' =>
     array(0) {
     }
     'extra_options' =>
     array(0) {
     }
   }
   */

3. The parser is unnecessarily complex and doesn't handle syntax errors properly:

   var_dump(
       VariantParser::parseCommandArguments(array('+mysql followed+ by- *garbage'))
   );
   /*
   array(3) {
     'enabled_variants' =>
     array(1) {
       'mysql' =>
       bool(true)
     }
     'disabled_variants' =>
     array(0) {
     }
     'extra_options' =>
     array(0) {
     }
   }
   */

4. The current implementation allows to specify path for a disabled variant which won't be used down the line:

   var_dump(
       VariantParser::parseCommandArguments(array('-openssl=/blah/blah'))
   );
   /*
   array(3) {
     'enabled_variants' =>
     array(0) {
     }
     'disabled_variants' =>
     array(1) {
       'openssl' =>
       string(10) "/blah/blah"
     }
     'extra_options' =>
     array(0) {
     }
   }
   */