Use CHECK_PRINTF() for printf-like functions in util_bug.h

changes/ticket32765

@@ -0,0 +1,4 @@
+  o Minor bugfixes (correctness checks):
+    - Use GCC/Clang's printf-checking feature to make sure that
+      tor_assertf() arguments are correctly typed. Fixes bug 32765;
+      bugfix on 0.4.1.1-alpha.

src/lib/log/util_bug.h

@@ -242,10 +242,12 @@
 
 void tor_assertion_failed_(const char *fname, unsigned int line,
                            const char *func, const char *expr,
-                           const char *fmt, ...);
+                           const char *fmt, ...)
+    CHECK_PRINTF(5,6);
 void tor_bug_occurred_(const char *fname, unsigned int line,
                        const char *func, const char *expr,
-                       int once, const char *fmt, ...);
+                       int once, const char *fmt, ...)
+  CHECK_PRINTF(6,7);
 
 void tor_abort_(void) ATTR_NORETURN;