Fix build --with-sound on NetBSD and OpenBSD

* configure.ac: Use ossaudio by default on *BSD systems.
(Bug#64698)

* etc/NEWS: Announce the change.

2 files changed, 16 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index 38ff6e18daf..79f5a468dd9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1800,12 +1800,15 @@ if test "${with_sound}" != "no"; then
     AC_MSG_ERROR([OSS sound support requested but not found.])
 
   if test "${with_sound}" = "bsd-ossaudio" || test "${with_sound}" = "yes"; then
-    # Emulation library used on NetBSD.
+    # OSS emulation library used on NetBSD and OpenBSD.
     AC_CHECK_LIB([ossaudio], [_oss_ioctl], [LIBSOUND=-lossaudio], [LIBSOUND=])
     test "${with_sound}" = "bsd-ossaudio" && test -z "$LIBSOUND" && \
       AC_MSG_ERROR([bsd-ossaudio sound support requested but not found.])
-    dnl FIXME?  If we did find ossaudio, should we set with_sound=bsd-ossaudio?
-    dnl Traditionally, we go on to check for alsa too.  Does that make sense?
+    # On {Net,Open}BSD use the system audio library instead of
+    # potentially switching to ALSA below, as ALSA on these appears to
+    # just wrap system libraries.
+    test "${with_sound}" = "yes" && test "$LIBSOUND" = "-lossaudio" && \
+      with_sound="bsd-ossaudio"
   fi
   AC_SUBST([LIBSOUND])
 
diff --git a/etc/NEWS b/etc/NEWS
index 5883b4df2a7..e81bc223836 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -24,6 +24,16 @@ applies, and please also update docstrings as needed.
 
 * Installation Changes in Emacs 30.1
 
+---
+** Emacs now defaults to ossaudio library for sound on NetBSD and OpenBSD.
+Previously configure used ALSA libraries if installed on the
+system when configured '--with-sound=yes' (which is the default), with
+fallback to libossaudio.  The libossaudio library included with the
+base system is now used even if ALSA is found to avoid relying on
+external packages and to resolve potential incompatibilities between
+Linux and BSD versions of ALSA.  Use '--with-sound=alsa' to build with
+ALSA on these operating systems instead.
+
 
 * Startup Changes in Emacs 30.1