tar src/extract.c: delayed_link uses strcpy into tail buffer

In src/extract.c, GNU tar constructs a struct delayed_link with a flexible tail member char target[1]. It allocates memory as offsetof(struct delayed_link,target)+strlen([REDACTED])+1, then copies into p->target using strcpy(p->target, [REDACTED]). If [REDACTED] originates from attacker-controlled archive fields and can be inconsistent with strlen inputs (e.g., embedded NULs or length/copy source mismatch), strcpy can overflow the allocated tail buffer (CWE-120/CWE-787 bug class).