add check for strlcpy dstsize zero

[vrilly]

Something that moulinette checks for and many students here fail on it.

Testing ft_strlcpy
 [!] Error for values "Je test un strncpy,
car j'aime bien ca!" with size "0" - Expected:  - Got: Je test un strncpy,
car j'aime bien ca! and Expected len: 39 - Got 39
 [!] Error for values "azlijazfpozekfpozefpoezfzef j'aime bien ca!" with size "0" - Expected:  - Got: azlijazfpozekfpozefpoezfzef j'aime bien ca! and Expected len: 43 - Got 43
 [*] ft_strlcpy : [ko]

[alelievr]

Thanks for your contribution !