[psaux] Fix Savannah bug #35657. If in function `skip_spaces' the routine `skip_comment' comes to the end of buffer, `cur' is still increased by one, so we need to check for `p >= limit' and not `p == limit'. * src/psaux/psconv.c (PS_Conv_Strtol, PS_Conv_ToFixed, PS_Conv_ASCIIHexDecode, PS_Conv_EexecDecode): Fix boundary checking.