Fix compilation warnings in dlz_perl_driver.c

Fix compilation warnings in dlz_perl_driver.c

    dlz_perl_driver.c: In function ‘dlz_version’:
    dlz_perl_driver.c:116:27: warning: unused parameter ‘flags’ [-Wunused-parameter]
      116 | dlz_version(unsigned int *flags) {
          |             ~~~~~~~~~~~~~~^~~~~
    In file included from /usr/lib64/perl5/CORE/perl.h:5685,
                     from dlz_perl_driver.c:33:
    dlz_perl_driver.c: In function ‘dlz_allnodes’:
    /usr/lib64/perl5/CORE/pp.h:162:26: warning: value computed is not used [-Wunused-value]
      162 | #define POPs            (*sp--)
          |                         ~^~~~~~
    dlz_perl_driver.c:151:17: note: in expansion of macro ‘POPs’
      151 |                 POPs;
          |                 ^~~~
    dlz_perl_driver.c: In function ‘dlz_allowzonexfr’:
    /usr/lib64/perl5/CORE/pp.h:162:26: warning: value computed is not used [-Wunused-value]
      162 | #define POPs            (*sp--)
          |                         ~^~~~~~
    dlz_perl_driver.c:251:17: note: in expansion of macro ‘POPs’
      251 |                 POPs;
          |                 ^~~~
    dlz_perl_driver.c: In function ‘dlz_findzonedb’:
    /usr/lib64/perl5/CORE/pp.h:162:26: warning: value computed is not used [-Wunused-value]
      162 | #define POPs            (*sp--)
          |                         ~^~~~~~
    dlz_perl_driver.c:328:17: note: in expansion of macro ‘POPs’
      328 |                 POPs;
          |                 ^~~~
    dlz_perl_driver.c: In function ‘dlz_lookup’:
    /usr/lib64/perl5/CORE/pp.h:162:26: warning: value computed is not used [-Wunused-value]
      162 | #define POPs            (*sp--)
          |                         ~^~~~~~
    dlz_perl_driver.c:407:17: note: in expansion of macro ‘POPs’
      407 |                 POPs;
          |                 ^~~~
    dlz_perl_driver.c:472:1: error: no previous prototype for ‘missing_perl_method’ [-Werror=missing-prototypes]
      472 | missing_perl_method(const char *perl_class_name, PerlInterpreter *my_perl)
          | ^~~~~~~~~~~~~~~~~~~
    dlz_perl_driver.c: In function ‘missing_perl_method’:
    dlz_perl_driver.c:485:9: error: ISO C90 forbids array ‘full_name’ whose size cannot be evaluated [-Werror=vla]
      485 |         char full_name[BUF_LEN];
          |         ^~~~
    dlz_perl_driver.c: In function ‘dlz_create’:
    dlz_perl_driver.c:613:13: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
      613 |         if (missing_method_name = missing_perl_method(perl_class_name, my_perl))
          |             ^~~~~~~~~~~~~~~~~~~
    /usr/lib64/perl5/CORE/pp.h:162:26: warning: value computed is not used [-Wunused-value]
      162 | #define POPs            (*sp--)
          |                         ~^~~~~~
    dlz_perl_driver.c:657:17: note: in expansion of macro ‘POPs’
      657 |                 POPs;
          |                 ^~~~
    dlz_perl_driver.c:502:15: warning: unused variable ‘init_args’ [-Wunused-variable]
      502 |         char *init_args[] = { NULL, NULL };
          |               ^~~~~~~~~