If we are at "warnings at compile time", MacOS clang thinks this about
current binkd sources:

Making depends...
Compiling ftnq.c...
ftnq.c:181:16: warning: comparison of array 'fn->pwd' equal to a null
pointer is always false [-Wtautological-pointer-compare]
fn->pwd == NULL || strcmp(fn->pwd, "-") == 0)
~~~~^~~ ~~~~
ftnq.c:319:33: warning: comparison of array 'node->pwd' equal to a null
pointer is always false [-Wtautological-pointer-compare]
if (node == NULL || node->pwd == NULL || strcmp(node->pwd, "-") == 0)
~~~~~~^~~ ~~~~
2 warnings generated.
Compiling protocol.c...
protocol.c:1262:17: warning: address of array 'pn->pwd' will always
evaluate to 'true' [-Wpointer-bool-conversion]
if (pn->pwd && strcmp(pn->pwd, "-") && state->to == 0)
~~~~^~~ ~~
protocol.c:1405:21: warning: address of array 'pn->pwd' will always
evaluate to 'true' [-Wpointer-bool-conversion]
if (pn && pn->pwd && strcmp(pn->pwd, "-") && state->to == 0)
~~ ~~~~^~~
protocol.c:1419:17: warning: address of array 'pn->pwd' will always
evaluate to 'true' [-Wpointer-bool-conversion]
if (pn->pwd && strcmp(pn->pwd, "-"))
~~~~^~~ ~~
protocol.c:1432:17: warning: address of array 'pn->pwd' will always
evaluate to 'true' [-Wpointer-bool-conversion]
if (pn->pwd && strcmp(pn->pwd, "-"))
~~~~^~~ ~~
4 warnings generated.
Compiling ftnnode.c...
ftnnode.c:150:18: warning: address of array 'pn->pwd' will always
evaluate to 'true' [-Wpointer-bool-conversion]
&& (!pn->pwd || strcmp(pn->pwd, "-") == 0)
~~~~~^~~
1 warning generated.
Compiling unix/daemonize.c...
unix/daemonize.c:33:5: warning: 'daemon' is deprecated: first deprecated
in macOS 10.5 - Use posix_spawn APIs instead. [-Wdeprecated-declarations]
if (daemon(nochdir, 0) == -1)
^
/usr/include/stdlib.h:293:6: note: 'daemon' has been explicitly marked deprecated here
int daemon(int, int) __DARWIN_1050(daemon) __OSX_AVAILABLE_BUT_DEPRECATED_MSG(__MAC_10_0, __MAC_10_5, __IPHONE_2_0, __IPHONE_2_0, "Us...
^
1 warning generated.

It does produce an runnable executable,
$ ./binkd -v
Binkd 1.1a-96 (Dec 13 2017 13:27:11/Darwin)
$ cc -v
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin17.3.0
....

but some of the warnings might point out logic that really isn't doing
what was expected, like the inverted pointers.

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* Origin: *** nntp://fidonews.mine.nu *** Finland *** (2:221/6.0)