patch 8.0.1832: cannot use :unlet for an environment variable commit https://github.com/vim/vim/commit/137374fd6538cf9dee0cb22907728d8fdecb5832 Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 13 15:59:50 2018 +0200 patch 8.0.1832: cannot use :unlet for an environment variable Problem: Cannot use :unlet for an environment variable. Solution: Make it work. Use unsetenv() if available. (Ken Takata, closes #2855)

TYPEMAP
VIWIN	T_VIOBJNOMUNGE
VIBUF	T_VIOBJNOMUNGE

INPUT
T_VIOBJNOMUNGE
	if (sv_isa($arg, \"${ntype}\")) {
	    IV tmp = SvIV((SV*)SvRV($arg));
	    $var = INT2PTR($type, tmp);
	    if (!tmp)
		croak(\"$ntype no longer exists\");
	}
	else
	    croak(\"$var is not of type ${ntype}\")