Now successfully completes VPATH build via `make distcheck'
Another try
removing AM_SILENT_RULES([yes]) from configure.ac temporarily
call ls
Now there is a target for webvtt-config.h in libwebvtt and libwebvttxx as well, which solves the VPATH and SRCDIR builds on my unix VM. perhaps Travis will survive
Merge branch 'build-system' of git://github.com/caitp/webvtt into cait-test