v.transform: add warning for columns option

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@52937 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.transform/main.c

@@ -211,8 +211,11 @@ int main(int argc, char *argv[])
 		    idx = IDX_ZSCALE;
 		else if (strcmp(tokens[0], zrot->key) == 0)
 		    idx = IDX_ZROT;
-		else
+		else {
+		    G_warning(_("Unknown column parameter '%s'"),
+		              tokens[0]);
 		    idx = -1;
+		}
 
 		if (idx != -1)
 		    columns_name[idx] = G_store(tokens[1]);