compile error with PAHO_USE_SELECT=ON since 1.3.16

[jwalt]

Describe the bug
Paho with PAHO_USE_SELECT=ON has some compile errors. This is new in 1.3.16, 1.3.15 compiles fine.

To Reproduce
Build 1.3.16 with cmake option PAHO_USE_SELECT=ON

Expected behavior
No compiler errors

Log files
Please try to attach log files rather than pasting the log contents. It makes the issues easier to read.

** Environment (please complete the following information):**

• OS: MingW compiler
• Version gcc 15.1/mingw 13.0

Additional context
Add any other context about the problem here.

paho.mqtt.c.log