Explicitly length(NAME) with typemaps other than T_PV

Previously, the length operator on typemaps other than T_PV would lead
to that length value not being initialized, leading to segfaults and
worse. Worse yet, parsexs would silently emit this erroneous code.

For now it will at least give a clear error, in the future we should
perhaps consider eliminating this limitation altogether.

Author: Leont

dist/ExtUtils-ParseXS/lib/ExtUtils/ParseXS/Node.pm

@@ -1407,7 +1407,9 @@ sub lookup_input_typemap {
         # as a pseudo-parameter, then override the normal typedef - which
         # would emit SvPV_nolen(...) - and instead, emit SvPV(...,
         # STRLEN_length_of_foo)
-        if ($xstype eq 'T_PV' and $self->{has_length}) {
+        if ($self->{has_length}) {
+            die "length(NAME) unsupported with typemaps other than T_PV"
+                if $xstype ne 'T_PV';
             die "default value not supported with length(NAME) supplied"
                 if defined $default;
             return "($type)SvPV($arg, STRLEN_length_of_$var);",