use-of-uninitialized-value in dprintf formatf

use-of-uninitialized-value in dprintf formatf: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). MemorySanitizer: use-of-uninitialized-value in function dprintf formatf in file curl/lib/mprintf.c