build: handle relative libexecdir instances

With earlier commit, we've used exec_dir to reference the path of obexd
and bluetoothd within the service files.

At the same time, in my testing I was providing the complete path on the
configure command line. As result, things just worked.

In the default case, the variable contains relative references to ${}
variables, which as result end up literal in the services. Ultimately
the service files were broken.

Document are reuse the existing pattern of manually expanding the
variables.

Fixes: #736

Makefile.am

@@ -16,7 +16,7 @@ CLEANFILES =
 
 EXTRA_DIST =
 
-pkglibexecdir = $(libexecdir)/bluetooth
+pkglibexecdir = @PKGLIBEXECDIR@
 
 pkglibexec_PROGRAMS =
 

configure.ac

@@ -401,6 +401,24 @@ if (test "${prefix}" = "NONE"); then
 	prefix="${ac_default_prefix}"
 fi
 
+if (test "${exec_prefix}" = "NONE"); then
+	# exec_prefix defaults to prefix, although our manual handling of the
+	# latter (above) confuses autoconf. Manually set the exec_prefix.
+	exec_prefix="${prefix}"
+fi
+
+# Expand any variables containing relative references like ${prefix} and co.
+#
+# Otherwise we'll end up with literal references in the final binaries or
+# manuals, which is not something we really want.
+
+if (test "$libexecdir" = '${exec_prefix}/libexec'); then
+	pkglibexecdir="${exec_prefix}/libexec/bluetooth"
+else
+	pkglibexecdir="${libexecdir}/bluetooth"
+fi
+AC_SUBST(PKGLIBEXECDIR, "${pkglibexecdir}")
+
 if (test "$localstatedir" = '${prefix}/var'); then
 	storagedir="${prefix}/var/lib/bluetooth"
 else

mesh/bluetooth-mesh.service.in

@@ -5,7 +5,7 @@ ConditionPathIsDirectory=/sys/class/bluetooth
 [Service]
 Type=dbus
 BusName=org.bluez.mesh
-ExecStart=@exec_prefix@/bluetooth/bluetooth-meshd
+ExecStart=@PKGLIBEXECDIR@/bluetooth-meshd
 NotifyAccess=main
 LimitNPROC=1
 ProtectHome=true

obexd/src/obex.service.in

@@ -4,7 +4,7 @@ Description=Bluetooth OBEX service
 [Service]
 Type=dbus
 BusName=org.bluez.obex
-ExecStart=@exec_prefix@/bluetooth/obexd
+ExecStart=@PKGLIBEXECDIR@/obexd
 
 [Install]
 Alias=dbus-org.bluez.obex.service

obexd/src/org.bluez.obex.service.in

@@ -1,4 +1,4 @@
 [D-BUS Service]
 Name=org.bluez.obex
-Exec=@exec_prefix@/bluetooth/obexd
+Exec=@PKGLIBEXECDIR@/obexd
 SystemdService=dbus-org.bluez.obex.service

src/bluetooth.service.in

@@ -6,7 +6,7 @@ ConditionPathIsDirectory=/sys/class/bluetooth
 [Service]
 Type=dbus
 BusName=org.bluez
-ExecStart=@exec_prefix@/bluetooth/bluetoothd
+ExecStart=@PKGLIBEXECDIR@/bluetoothd
 NotifyAccess=main
 #WatchdogSec=10
 #Restart=on-failure

tools/bluetooth-logger.service.in

@@ -4,7 +4,7 @@ ConditionPathIsDirectory=/sys/class/bluetooth
 
 [Service]
 Type=simple
-ExecStart=@exec_prefix@/bluetooth/btmon-logger -p -b /var/log/bluetooth/hci.log
+ExecStart=@PKGLIBEXECDIR@/btmon-logger -p -b /var/log/bluetooth/hci.log
 NotifyAccess=main
 CapabilityBoundingSet=CAP_NET_RAW
 LimitNPROC=1