Fix genecodes_c on FreeBSD

Unfortunately the existing CPATH/C_INCLUDE_PATH logic makes this a bit
hard to generalize.

docs/changelog.rst

@@ -8,6 +8,8 @@ Changelog
 
 - Slightly faster reading of events.
 
+- Fix build on FreeBSD.
+
 
 1.8.0 (Jan 25, 2025)
 ====================

setup.py

@@ -2,6 +2,7 @@
 import sys
 import shutil
 import textwrap
+import platform
 from pathlib import Path
 from subprocess import run
 
@@ -24,8 +25,13 @@ def create_ecodes(headers=None):
         if c_inc_path:
             include_paths.update(c_inc_path.split(":"))
 
-        include_paths.add("/usr/include")
-        files = ["linux/input.h", "linux/input-event-codes.h", "linux/uinput.h"]
+        if platform.system().lower() == "freebsd":
+            include_paths.add("/usr/include/dev/evdev")
+            files = ["input.h", "input-event-codes.h", "uinput.h"]
+        else:
+            include_paths.add("/usr/include")
+            files = ["linux/input.h", "linux/input-event-codes.h", "linux/uinput.h"]
+
         headers = [os.path.join(path, file) for path in include_paths for file in files]
 
     headers = [header for header in headers if os.path.isfile(header)]