add a --with-readline configure option for people to explicitly control support for the external library

git-svn-id: https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk@1791 b68d4a1b-bc3d-0410-92ed-d4ac073336b7

urjtag/ChangeLog

@@ -1,3 +1,8 @@
+2010-06-16  Mike Frysinger  <vapier@gentoo.org>
+
+  * acinclude.m4 (VL_LIB_READLINE): Add a --with[out]-readline configure
+    option so people can explicitly control support for the library.
+
 2010-06-15  Mike Frysinger  <vapier@gentoo.org>
 
   * src/bus/s3c4510x.c: Punt dead/useless cvs log info.

urjtag/acinclude.m4

@@ -48,6 +48,13 @@ dnl @author Ville Laurikari <vl@iki.fi>
 dnl @author Ville Voipio <vv@iki.fi>; check for readline completion (not available in, e.g. Leopard)
 
 AC_DEFUN([VL_LIB_READLINE], [
+  AC_ARG_WITH([readline],
+    [AS_HELP_STRING([--without-readline],
+      [support command completion/history])])
+  AS_IF([test "x$with_readline" = "xno"], [
+    vl_cv_lib_readline=no
+  ])
+
   AC_CACHE_CHECK([for a readline compatible library],
                  vl_cv_lib_readline, [
     ORIG_LIBS="$LIBS"
@@ -94,6 +101,8 @@ AC_DEFUN([VL_LIB_READLINE], [
     if test "$vl_cv_lib_readline_completion" = "yes"; then
       AC_DEFINE(HAVE_READLINE_COMPLETION, 1, [Define if your readline library has \`rl_completion_matches'])
     fi
+  elif test "$with_readline$vl_cv_lib_readline" = "yesno" ; then
+    AC_ERROR([readline support requested, but none found])
   fi
 
 ])dnl