Commmon mistakes

[Roland Illig]

Hi,

building man2hlp failed for me because g_strlcpy is unknown to the 
linker. (I'm using glib-1.2.) I have reverted the last patch for it.

I think we could collect such mistakes in the HACKING file to never do 
them again. What I would like to see there is:

- incompatibilities between operating systems
- library incompatibilities
- not-so-good functions (str{,n}cpy) and how to replace them

Roland