ZXID: Some more forward compat.

The variable zx_debug was renamed to errmac_debug on 2013-11-13.

The fields wsp_localpdp_obl_req and wsc_localpdp_obl_accept in
struct zxid_conf are no longer strings but arrays.

These changes seem to be sufficient to be able to link against
current libzxid.
Build [win32]: Some compilers (eg cl) don't like __attribute__.
Fixed for(i;i<x;i++); crash

The code will no longer generate invalid F_LT/GT etc nodes when asked
to, instead it will generate a function call to the correct efun.

I still do not know why this worked in pike 7.8.

Next step: Make treeopt.in F_LT match CALL(&f_lt,ARGS(...))

(cherry picked from commit 89424bfaa34ee5639b0ab2fedccebec96703ffa8)
Make illegal percent encodings throw exception, as per testsuite.
Adjust to current _Roxen behavior. We may chose to reverse this later.