* Small wording fix

configure

@@ -1046,7 +1046,7 @@ Optional Packages:
                           both]
   --with-tags[=TAGS]
                           include additional configurations [automatic]
-  --with-rrdtool-source   Specify directory where rrdtool sources are
+  --with-rrdtool-source   Specify that you have the rrdtool sources in the main build dir
   --with-xml-prefix=PFX   Prefix where libxml is installed (optional)
   --with-xml-exec-prefix=PFX Exec prefix where libxml is installed (optional)
@@ -19497,7 +19497,7 @@ if test "${with_rrdtool_source+set}" = set; then
 subdirs="$subdirs rrdtool"
-		RRDTOOL_LIBS="$top_builddir/rrdtool/src/.libs/librrdtool.a"
+		RRDTOOL_LIBS="\$(top_builddir)/rrdtool/src/.libs/librrdtool.a"
 else

configure.ac

@@ -43,10 +43,10 @@ AC_CHECK_LIB([ncurses], [curses_version])
 AC_CHECK_LIB([panel], [panel_window])
 
 AC_ARG_WITH([rrdtool-source],
-	[  --with-rrdtool-source   Specify directory where rrdtool sources are],
+	[  --with-rrdtool-source   Specify that you have the rrdtool sources in the main build dir],
 	[
 		AC_CONFIG_SUBDIRS(rrdtool)
-		RRDTOOL_LIBS="$top_builddir/rrdtool/src/.libs/librrdtool.a"
+		RRDTOOL_LIBS="\$(top_builddir)/rrdtool/src/.libs/librrdtool.a"
 	],
 	[
 	AC_CHECK_LIB([rrd], [rrd_create],have_librrd=yes,,"-lm")