* configure.ac: removed the "null" frontend. just don't attach any frontend

if you do not want any.

configure.ac

@@ -36,8 +36,6 @@ AC_ARG_ENABLE(x11,
   [  --enable-x11            X11 support (autodetected)])
 AC_ARG_ENABLE(gl,
   [  --enable-gl             OpenGL support (autodetected)])
-AC_ARG_ENABLE(null,
-  [  --enable-null           Null driver support (autodetected)])
 
 dnl example programs features
 AC_ARG_ENABLE(imlib2,
@@ -139,12 +137,6 @@ if test "${enable_gl}" != "no"; then
   fi
 fi
 
-if test "${enable_null}" != "no"; then
-  ac_cv_my_have_null="yes"
-  AC_DEFINE(USE_NULL, 1, Define to activate the Null backend driver)
-  CACA_DRIVERS="${CACA_DRIVERS} null"
-fi
-
 if test "${enable_ncurses}" != "no"; then
   ac_cv_my_have_ncurses="no"
   AC_CHECK_HEADERS(curses.h ncurses.h,