Make pyserial work in DragonflyBSD properly

0001-add-DragonFlyBSD.patch

From 87e58dcc9e372de8399676d9151b634f69ad821d Mon Sep 17 00:00:00 2001
From: Joe Hu <vegertar@gmail.com>
Date: Sat, 25 Feb 2023 08:47:44 +0800
Subject: [PATCH] add DragonFlyBSD

---
 serial/serialposix.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/serial/serialposix.py b/serial/serialposix.py
index 0464075..6ec4334 100644
--- a/serial/serialposix.py
+++ b/serial/serialposix.py
@@ -243,7 +243,8 @@ elif plat[:6] == 'darwin':   # OS X
 elif plat[:3] == 'bsd' or \
      plat[:7] == 'freebsd' or \
      plat[:6] == 'netbsd' or \
-     plat[:7] == 'openbsd':
+     plat[:7] == 'openbsd' or \
+     plat[:9] == 'dragonfly':
 
     class ReturnBaudrate(object):
         def __getitem__(self, key):
@@ -270,7 +271,7 @@ elif plat[:3] == 'bsd' or \
 
 else:
     class PlatformSpecific(PlatformSpecificBase):
-        pass
+        raise NotImplementedError(plat)
 
 
 # load some constants for later use.
@@ -677,7 +678,11 @@ class Serial(SerialBase, PlatformSpecific):
         """
         if not self.is_open:
             raise PortNotOpenError()
-        termios.tcdrain(self.fd)
+        # termios.tcdrain(self.fd)
+        # poll to prevent from hanging forever
+        while self.out_waiting:
+            import time
+            time.sleep(0.05)
 
     def _reset_input_buffer(self):
         """Clear input buffer, discarding all that is in the buffer."""
-- 
2.38.1