[softmaxe]

Summary

Dead-code audit result: no unused functions, macros, extern declarations, or files. Two small leftovers are removed, and the deprecation suppression is narrowed so it stops hiding new deprecations.

 ferry.m
-#include <unistd.h>
 parse_positive
-  return (end && *end == '\0' && ...
+  return (*end == '\0' && ...
+process_pid                  // sole GetProcessPID caller, pragma scoped here
 main
-  #pragma ... ignored "-Wdeprecated-declarations"   // covered all of main
-  GetProcessPID(&front, &pid)
+  pid = process_pid(&front)

 tests/follow.m
-  pragma covered restore_app and main
+  pragma covers restore_app only

This matches upstream yabai, which also scopes this suppression to individual functions.

Evidence

• Before: the -Wdeprecated-declarations pragma covers the whole of main for two GetProcessPID calls, so -Werror cannot catch a new deprecation there.
  After: with the build flags CI uses, CFLAGS="-O2 -Werror" make all test build/follow-test passes: 10 CLI checks and 3 binary checks, and the live test compiles.
• clang -Wunused -Wunused-macros -Wunreachable-code-aggressive reports nothing on src/ferry.m or tests/follow.m.
• make test-follow was not run: it switches Spaces on a live desktop.

Merge Danger

Door: two-way

Blast Radius: small

The PID lookup is now behind process_pid(), which returns 0 on failure. Both callers handled 0 before, so behavior should not change, but no automated test covers this path on CI.