Windows: use default ZLIB1 unless --with-zlib-lib is set

Reviewed-by: NAndy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1772)

Configurations/00-base-templates.conf

@@ -80,10 +80,11 @@
             sub {
                 unless ($disabled{zlib}) {
                     if (defined($disabled{"zlib-dynamic"})) {
-                        return $withargs{zlib_lib};
+                        return $withargs{zlib_lib} // "ZLIB1";
                     }
                 }
-                return (); },
+                return ();
+            },
 
         ld              => "link",
         lflags          => "/nologo",