[fvwmorg/fvwm3] e423e7: read: remove custom fgets logic and use fparseln()

  Branch: refs/heads/ta/fparseln
  Home:   https://github.com/fvwmorg/fvwm3
  Commit: e423e76e786ef937bb33cd8ae96bb5da3b19be69
      https://github.com/fvwmorg/fvwm3/commit/e423e76e786ef937bb33cd8ae96bb5da3b19be69
  Author: Thomas Adam <[email protected]>
  Date:   2019-05-15 (Wed, 15 May 2019)

  Changed paths:
    M .travis.yml
    M configure.ac
    M fvwm/Makefile.am
    M fvwm/read.c

  Log Message:
  -----------
  read: remove custom fgets logic and use fparseln()

When reading in a configuration file (or anything which uses the
Read/PipeRead command), there's always been a hard-limit of a
configuration line being no more than 1024 bytes.  This was fine
historically, but this restriction is now rather limiting.

This change solves that by using fparseln() from libbsd.  This also has
the added advantage that it can handle line continuations, which was
also part of the hand-rolled logic mentioned above.

Because of this change, there's now a hard dependency on libbsd for
non-BSD systems.