Avoid explicit calls to select.select()

Use higher level `selectors` module instead:

https://docs.python.org/3/library/selectors.html.

Selectors uses the most efficient implementation available on the
current platform. On Linux, it defaults to using:

```
$ python3 -c "import selectors; print(selectors.DefaultSelector())"
<selectors.EpollSelector object at 0x7a6a66f02120>
```

Author: jukuisma

exiftool/exiftool.py

@@ -30,7 +30,7 @@
 """
 
 # ---------- standard Python imports ----------
-import select
+import selectors
 import subprocess
 import os
 import shutil
@@ -114,6 +114,10 @@ def _read_fd_endswith(fd, b_endswith: bytes, block_size: int) -> bytes:
 
 		if you're not careful, on windows, this will block
 	"""
+	if not constants.PLATFORM_WINDOWS:
+		selector = selectors.DefaultSelector()
+		selector.register(fd, selectors.EVENT_READ)
+
 	output_list: List[bytes] = []
 
 	# if we're only looking at the last few bytes, make it meaningful.  4 is max size of \r\n? (or 2)
@@ -129,9 +133,9 @@ def _read_fd_endswith(fd, b_endswith: bytes, block_size: int) -> bytes:
 			output_list.append(os.read(fd, block_size))
 		else:  # pytest-cov:windows: no cover
 			# this does NOT work on windows... and it may not work on other systems... in that case, put more things to use the original code above
-			inputready, outputready, exceptready = select.select([fd], [], [])
-			for i in inputready:
-				if i == fd:
+			events = selector.select()
+			for key, _ in events:
+				if key.fd == fd:
 					output_list.append(os.read(fd, block_size))
 
 	return b"".join(output_list)