Fix missing errno for library calls

[Elias481]

Fix to enable inotify errno + message in Exceptions resulting from unsuccessfull library calls.

[coveralls]

Coverage decreased (-2.8%) to 82.258% when pulling 3fc523146c305947e4be45e3a1a8d9194502c29a on Elias481:fix-missing-errno-for-library-calls into 288a2b01fd4a726dc68d960f8351630aee788a13 on dsoprea:master.

[Elias481]

Coverage decreased (-2.8%) to 82.258% when pulling 3fc5231 on Elias481:fix-missing-errno-for-library-calls into 288a2b0 on dsoprea:master.

The coverall report is not really good working... The overall coverage did increase and not decrease with my additional commit 3fc5231... (~ 86,3 overall not 82,258%..) It compares the percentage of only few files to the previous percentage of all files or whichever combination of file had been selected on that run?

[dsoprea]

Let's squash these commits together, and revisit how we're getting the errno integer and string into the exception messages. Detailed in comment.