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>

common/build-info.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cstdio>
+
 int llama_build_number(void);
 
 const char * llama_commit(void);
@@ -8,4 +10,4 @@ const char * llama_compiler(void);
 const char * llama_build_target(void);
 const char * llama_build_info(void);
 
-void llama_print_build_info(const char *);
+void llama_print_build_info(const char *, FILE * = stderr);