overflow is falsely thrown
<h3><details><summary>Original Reporter info from Mantis: <small>helbig</small></summary><small>
- **Reporter name:** Wolfgang Helbig
</small></details></h3>
## Description:
``` pascal
The following program will abort with an overflow error for no apperant reason.
{$MODE ISO}
{$Q+}
program nabs(input, output);
type halfword = 0..65535;
var a, b: halfword;
begin
a := 4095;
b := 4096;
if abs(int(a+b-8192)) < 4096 then writeln('ok');
end.
```
## Steps to reproduce:
$ fpc nabs.p<br/>
$ nabs<br/>
Runtime error 215 at $000000010DE69401<br/>
``` $000000010DE69401```<br/>
## Mantis conversion info:
- **Mantis ID:** 37875
- **OS:** os x
- **OS Build:** 10.11
- **Platform:** imac
- **Version:** 3.2.0
- **Monitored by:** » helbig (Wolfgang Helbig)
issue