Adjust helptext in m4/systemd.m4

Use AS_HELP_STRING for proper formating, mention both options take a
directory, mention the default value, quote the arguments in brackets.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
[ijc -- ran autogen.sh as requested]
Acked-by: Ian Campbell <ian.campbell@citrix.com>

m4/systemd.m4

@@ -18,12 +18,16 @@
 
 dnl Some optional path options
 AC_DEFUN([AX_SYSTEMD_OPTIONS], [
-	AC_ARG_WITH(systemd, [  --with-systemd          set directory for systemd service files],
-		SYSTEMD_DIR="$withval", SYSTEMD_DIR="")
+	AC_ARG_WITH(systemd,
+		AS_HELP_STRING([--with-systemd=DIR],
+		[set directory for systemd service files [PREFIX/lib/systemd/system]]),
+		[SYSTEMD_DIR="$withval"],[SYSTEMD_DIR=""])
 	AC_SUBST(SYSTEMD_DIR)
 
-	AC_ARG_WITH(systemd, [  --with-systemd-modules-load          set directory for systemd modules load files],
-		SYSTEMD_MODULES_LOAD="$withval", SYSTEMD_MODULES_LOAD="")
+	AC_ARG_WITH(systemd,
+		AS_HELP_STRING([--with-systemd-modules-load=DIR],
+		[set directory for systemd modules load files [PREFIX/lib/modules-load.d/]]),
+		[SYSTEMD_MODULES_LOAD="$withval"], [SYSTEMD_MODULES_LOAD=""])
 	AC_SUBST(SYSTEMD_MODULES_LOAD)
 ])
 

tools/configure

@@ -1509,8 +1509,11 @@ Optional Packages:
                           dependencies resolved we'll enable the C xenstored
                           for you. If you ask for oxenstored we'll complain
                           until you resolve those dependencies
-  --with-systemd          set directory for systemd service files
-  --with-systemd-modules-load          set directory for systemd modules load files
+  --with-systemd=DIR      set directory for systemd service files
+                          [PREFIX/lib/systemd/system]
+  --with-systemd-modules-load=DIR
+                          set directory for systemd modules load files
+                          [PREFIX/lib/modules-load.d/]
 
 Some influential environment variables:
   CC          C compiler command