3 files changed, 12 insertions, 0 deletions
diff --git a/audio/out/ao_alsa.c b/audio/out/ao_alsa.c
index 900cbafd03..050aef4e2c 100644
--- a/audio/out/ao_alsa.c
+++ b/audio/out/ao_alsa.c
@@ -49,6 +49,10 @@
 #include "internal.h"
 #include "audio/format.h"
 
+#if !HAVE_GPL
+#error GPL only
+#endif
+
 struct ao_alsa_opts {
     char *mixer_device;
     char *mixer_name;
diff --git a/audio/out/ao_jack.c b/audio/out/ao_jack.c
index 597835c989..b5413f77cf 100644
--- a/audio/out/ao_jack.c
+++ b/audio/out/ao_jack.c
@@ -40,6 +40,10 @@
 
 #include <jack/jack.h>
 
+#if !HAVE_GPL
+#error GPL only
+#endif
+
 struct jack_opts {
     char *port;
     char *client_name;
diff --git a/audio/out/ao_oss.c b/audio/out/ao_oss.c
index eebd9622e7..72413cd9f8 100644
--- a/audio/out/ao_oss.c
+++ b/audio/out/ao_oss.c
@@ -49,6 +49,10 @@
 #include "ao.h"
 #include "internal.h"
 
+#if !HAVE_GPL
+#error GPL only
+#endif
+
 // Define to 0 if the device must be reopened to reset it (stop all playback,
 // clear the buffer), and the device should be closed when unused.
 // Define to 1 if SNDCTL_DSP_RESET should be used to reset without close.