common : make build info output stream configurable (#28322)
Let llama_print_build_info write to a caller-provided FILE* instead of
hardcoding stderr. The parameter defaults to stderr so existing callers
keep their current behavior.
The version command in llama-app now passes stdout, so plain version
output goes to stdout where users expect it.
Signed-off-by: Adrien Gallouët <angt@huggingface.co>
