[PATCH] build: modifing behavior of systemdunitdir switch

[Paul Seidler <pl.seidler@googlemail.com>]

Currently it's not possible to disable the installation of the systemd
service file. If you use --without the file get installed into /no/.

Changes with this patch:
--without-systemdunitdir disables the installation of the service file
--with-systemdunitdir installs the file in the directory reported by
pkg-config
--with-systemdunitdir=/foo installs the file to /foo

Without giving the systemdunitdir switch, pkg-config checks for systemd and
installs the file if available.
---
 configure.ac |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index 5b81f28..b96dc5d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -62,14 +62,18 @@ if (test "${enable_capng}" = "yes"); then
 	AC_DEFINE(HAVE_CAPNG, 1, [Define to 1 if you have capabilities library.])
 fi
 
-AC_ARG_WITH([systemdunitdir], AC_HELP_STRING([--with-systemdunitdir=DIR],
-	[path to systemd system service directory]), [path_systemdunit=${withval}],
-		[path_systemdunit="`$PKG_CONFIG --variable=systemdsystemunitdir systemd`"])
-if (test -n "${path_systemdunit}"); then
-	SYSTEMD_UNITDIR="${path_systemdunit}"
-	AC_SUBST(SYSTEMD_UNITDIR)
-fi
-AM_CONDITIONAL(SYSTEMD, test -n "${path_systemdunit}")
+AC_ARG_WITH([systemdunitdir],
+	AC_HELP_STRING([--with-systemdunitdir@<:@=DIR@:>@],
+		[Installing systemd service file (auto)
+		@<:@path to systemd system service directory@:>@]),
+	[path_systemdunit="${withval}"],
+	[PKG_CHECK_MODULES(SYSTEMD, systemd,
+		path_systemdunit=yes, path_systemdunit=no)])
+AS_IF([test "${path_systemdunit}" = yes],
+	[path_systemdunit="`$PKG_CONFIG --variable=systemdsystemunitdir systemd`"])
+AS_IF([test "${path_systemdunit}" != no],
+	[AC_SUBST(SYSTEMD_UNITDIR,["${path_systemdunit}"])])
+AM_CONDITIONAL(SYSTEMD, test "${path_systemdunit}" != no)
 
 AC_OUTPUT(Makefile scripts/bluetooth.rules doc/version.xml
 			src/bluetoothd.8 src/bluetooth.service bluez.pc)
-- 
1.7.8.1