Merge branch 'jc/varargs-attributes'

Varargs functions that are unannotated as printf-like or execl-like
have been annotated as such.

* jc/varargs-attributes:
  __attribute__: add a few missing format attributes
  __attribute__: mark some functions with LAST_ARG_MUST_BE_NULL
  __attribute__: remove redundant attribute declaration for git_die_config()
  __attribute__: trace2_region_enter_printf() is like "printf"

wt-status.c

@@ -126,6 +126,7 @@ void status_printf(struct wt_status *s, const char *color,
 	va_end(ap);
 }
 
+__attribute__((format (printf, 3, 4)))
 static void status_printf_more(struct wt_status *s, const char *color,
 			       const char *fmt, ...)
 {