v4.19.13 snapshot.
diff --git a/tools/lib/api/debug.c b/tools/lib/api/debug.c
new file mode 100644
index 0000000..69b1ba3
--- /dev/null
+++ b/tools/lib/api/debug.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdarg.h>
+#include "debug.h"
+#include "debug-internal.h"
+
+static int __base_pr(const char *format, ...)
+{
+ va_list args;
+ int err;
+
+ va_start(args, format);
+ err = vfprintf(stderr, format, args);
+ va_end(args);
+ return err;
+}
+
+libapi_print_fn_t __pr_warning = __base_pr;
+libapi_print_fn_t __pr_info = __base_pr;
+libapi_print_fn_t __pr_debug;
+
+void libapi_set_print(libapi_print_fn_t warn,
+ libapi_print_fn_t info,
+ libapi_print_fn_t debug)
+{
+ __pr_warning = warn;
+ __pr_info = info;
+ __pr_debug = debug;
+}