[Lazarus] CHM help package

[Werner Pamler]

Am 11.12.2017 um 18:32 schrieb Werner Pamler via Lazarus:
> I cloned your repo on my HD, and went through it step by step while 
> always trying to build lhelp, I could remove everything from the 
> folder chm except for these units: chmfifimain, chmreader, chmsitemap, 
> chmtypes (and chmobjinstance.inc). I think it is possible to extract 
> the essential changes from these units to get at least the new reading 
> functionality. I can try this - but: before beginning I'd like to get 
> positive feedback from fpc devs that this will be merged (I have some 
> old patches hanging around there, and it is not always motivating to 
> submit fpc patches).
>
> As for the unit lcid_conv: This fits into Lazarus' LazUtils, and 
> should go there independently of how this story ends here. I have 
> commit rights to Lazarus and can put it there. Any objections?

Sergey, I loaded a chm having codepage iso-8859-1 into your modified 
lhelp. It crashes in TIpChmDataProvider.DetectHtmlCodepage when trying 
to convert the string 88591 to a Word. Also, this codepage (as well as 
the other iso's) are not considered in lclid_conv.