Some of these are pretty hairy and it's a moving codebase. Since they are applying compiler "printf-like" attribute to functions which are using their own functions rather than libc printf, and we are purely making this change to disable the spurious warning because there is no abort in their %n handling, can't we just disable the annotations instead?
Index: patches/patch-src_mytypes_h =================================================================== RCS file: patches/patch-src_mytypes_h diff -N patches/patch-src_mytypes_h --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ patches/patch-src_mytypes_h 20 Sep 2021 09:28:21 -0000 @@ -0,0 +1,20 @@ +$OpenBSD$ + +Don't do printf-like checks on OpenBSD, which warn about %n use. + +Index: src/mytypes.h +--- src/mytypes.h.orig ++++ src/mytypes.h +@@ -33,7 +33,11 @@ local_scan.h includes it and exim.h includes them both + the arguments of printf-like functions. This is done by a macro. */ + + #if defined(__GNUC__) || defined(__clang__) +-# define PRINTF_FUNCTION(A,B) __attribute__((format(printf,A,B))) ++# if defined(__OpenBSD__) ++# define PRINTF_FUNCTION(A,B) /**/ ++# else ++# define PRINTF_FUNCTION(A,B) __attribute__((format(printf,A,B))) ++# endif + # define ARG_UNUSED __attribute__((__unused__)) + # define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__)) + # define ALLOC __attribute__((malloc))
