[FFADO-devel] r2189: Change in method of jack version detection

[Jonathan W. <jw...@ju...>]

Hi everyone

A while back we added a test on the jack version as part of an automatic
determination of whether the new libffado API version can be used.  This
utilised pkg-config and obviously will only give a reliable answer if the
jackd development files are present on the system.

In most distributions, these files are in a separate jack-devel package
which most users will not normally have installed.  In this case the version
detection will fail and (to aid distribution packagers) scons will assume a
new jack will ultimately be used.  This has caused a number of people to
compile svn trunk recently and end up with an "incompatible" FFADO version
for their distribution-supplied jack (which expected the old FFADO API).

Revision 2189 checks in what I hope is a solution to this.  Instead of
relying soley on pkg-config, scons first tries "jackd --version".  I am
hoping this makes life easier for users compiling trunk on systems with
an older jackd.

I have tested this with jack1 installed and uninstalled, and it seems to
work as expected on my system.  Since the format of the version query from
jack2 is the same I expect things to be ok in that case too, but I haven't
explicitly verified this.  There is also a chance that I've stuffed some
corner case up; if this is the case please let me know and we'll fix it.  I
apologise in advance if any error on my part causes an inconvenience.

Regards
  jonathan