Do not initialize a local variable soon to be assigned.
MODIFY
mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
@@ -84,7 +84,7 @@ dirname(mrb_state *mrb, const char *path)
static source_file*
source_file_new(mrb_state *mrb, mrb_debug_context *dbg, char *filename)
{
- source_file *file = NULL;
+ source_file *file;
file = (source_file*)mrb_malloc(mrb, sizeof(source_file));

Do not initialize a local variable soon to be assigned.