Description of problem:

When something bad happens to a serial port device and operations on it
start returning failures, they are being ignored due to minicom's lack of
error checking.

Example of such failure is physical removal of the hardware. ioctl()s on the
gone adapter's filedescriptor will start returning failures which will get
ingored (and select() will return immediately without an complain) which will
result in an infinite loop.

Version-Release number of selected component (if applicable):

minicom-2.2-2.fc6

Steps to Reproduce:
1. Start minicom
2. Forcibly remove the device driver module, or the hardware
  
Actual results:

Minicom looping infinitely.

Expected results:

Exit with an error message.

Additional info:

I attach the diff of the change that fixed the problem for me.