Patching libgnat with strlcpy and strlcat to remove warnings

Hello,

for gcc ada toolchain, libgnat uses several strcpy and strcat that spawn
the annoying warnings of strcpy and strcat on each compilation. I think
it may be a good idea to add some patches to fix this situation with
strlcpy. I am willing to do it in case it is ok and could be merged.

Cheers