For travis use `cmake --build . --target check` instead of `make check`.
For travis use `cmake --build . --target check` instead of `make check`.

Using cmake works regardless of what build system is chosen on the different
target platforms. In particular, this should make it work for Windows builds.

librsync/librsync,sourcefrog/librsync,sourcefrog/librsync,librsync/librsync,sourcefrog/librsync,dbaarda/librsync,dbaarda/librsync,librsync/librsync,dbaarda/librsync,dbaarda/librsync,librsync/librsync,sourcefrog/librsync