-case $with_modlib in
-no|none)
- use_modlib=none
-;;
-modplug)
- DX_CHECK_LIBMODPLUG([use_modlib=modplug], [])
-;;
-auto)
- DX_CHECK_LIBMODPLUG([have_libmodplug=yes], [have_libmodplug=no])
+use_modlib=none
+AS_CASE([$with_modlib],
+ [no|none], [:],
+ [modplug], [DX_LIB_LIBMODPLUG([use_modlib=modplug])],
+ [auto], [DX_LIB_LIBMODPLUG([use_modlib=modplug], [:])],
+ [AC_MSG_ERROR([Invalid argument to --with-modlib: $with_modlib])])