Remove the requirement for Avahi in the systemd startup file unless Avahi is included in the build.

.gitignore

@@ -25,6 +25,7 @@ stamp-h1
 man/Makefile
 man/Makefile.in
 scripts/shairport-sync.service
+scripts/shairport-sync.service-avahi
 scripts/shairport-sync
 shairport-sync.core
 gitversion.h

Makefile.am

@@ -236,8 +236,12 @@ if INSTALL_SYSTEMD
 	getent group shairport-sync &>/dev/null || groupadd -r shairport-sync >/dev/null
 	getent passwd shairport-sync &> /dev/null || useradd -r -M -g shairport-sync -s /usr/bin/nologin -G audio shairport-sync >/dev/null
 	[ -e $(DESTDIR)$(systemdsystemunitdir) ] || mkdir -p $(DESTDIR)$(systemdsystemunitdir)
+if USE_AVAHI
+	[ -e $(DESTDIR)$(systemdsystemunitdir)/shairport-sync.service ] || cp scripts/shairport-sync.service-avahi $(DESTDIR)$(systemdsystemunitdir)/shairport-sync.service
+else
 	[ -e $(DESTDIR)$(systemdsystemunitdir)/shairport-sync.service ] || cp scripts/shairport-sync.service $(DESTDIR)$(systemdsystemunitdir)
 endif
+endif
 if INSTALL_FREEBSD_SERVICE
   # Choose a uid and gid of 801 completely arbitrarity, except that it should be below 1000. FreeBSD doesn't seem to allow you to say "an ID in the range of..."
 	pw showgroup shairport-sync > /dev/null 2>&1 || pw addgroup -n shairport-sync -g 801 > /dev/null 2>&1

configure.ac

@@ -230,6 +230,9 @@ if test "x$with_avahi" = "xyes" ; then
   AC_DEFINE([CONFIG_AVAHI], 1, [Include Avahi-based mDNS support.])
   AC_CHECK_LIB([avahi-client], [avahi_client_new], , AC_MSG_ERROR(Avahi support requires the avahi-client library!))
   AC_CHECK_LIB([avahi-common],[avahi_strerror], , AC_MSG_ERROR(Avahi support requires the avahi-common library!))
+  AC_CONFIG_FILES([scripts/shairport-sync.service-avahi])
+else
+  AC_CONFIG_FILES([scripts/shairport-sync.service])
 fi
 AM_CONDITIONAL([USE_AVAHI], [test "x$with_avahi" = "xyes"])
 
@@ -473,6 +476,7 @@ AC_FUNC_ERROR_AT_LINE
 AC_FUNC_FORK
 AC_CHECK_FUNCS([atexit clock_gettime gethostname inet_ntoa memchr memmove memset mkfifo pow select socket stpcpy strcasecmp strchr strdup strerror strstr strtol strtoul])
 
-AC_CONFIG_FILES([Makefile man/Makefile scripts/shairport-sync.service])
+# Note -- there are AC_CONFIG_FILES directives further back, conditional on Avahi
+AC_CONFIG_FILES([Makefile man/Makefile])
 AC_CONFIG_FILES([scripts/shairport-sync],[chmod +x scripts/shairport-sync])
 AC_OUTPUT

scripts/shairport-sync.service-avahi.in

@@ -0,0 +1,15 @@
+[Unit]
+Description=Shairport Sync - AirPlay Audio Receiver
+After=sound.target
+Requires=avahi-daemon.service
+After=avahi-daemon.service
+Wants=network-online.target
+After=network.target network-online.target
+
+[Service]
+ExecStart=@prefix@/bin/shairport-sync
+User=shairport-sync
+Group=shairport-sync
+
+[Install]
+WantedBy=multi-user.target

scripts/shairport-sync.service.in

@@ -1,8 +1,6 @@
 [Unit]
 Description=Shairport Sync - AirPlay Audio Receiver
 After=sound.target
-Requires=avahi-daemon.service
-After=avahi-daemon.service
 Wants=network-online.target
 After=network.target network-online.target