Modernize jack configure tests using pkgconf

Supports both jack's and pipewire's implementations

mythtv/configure

@@ -5720,9 +5720,7 @@ check_header soundcard.h
 
 enabled alsa && check_lib alsa alsa/asoundlib.h snd_pcm_htimestamp -lasound
 
-enabled jack && check_lib jack jack/jack.h jack_client_open -ljack &&
-    check_func jack_port_get_latency_range -ljack &&
-    enable audio_jack
+enabled jack && use_pkg_config libjack jack jack/jack.h jack_port_get_latency_range && enable audio_jack || disable audio_jack
 
 # PulseAudio probe
 ! disabled audio_pulse &&