-case $with_gsl in
-no)
- have_gsl=no
-;;
-yes)
- DX_CHECK_GSL([1.0], [have_gsl=yes])
-;;
-*)
- DX_CHECK_GSL([1.0], [have_gsl=yes], [have_gsl=no])
-;;
-esac
-
+AS_CASE([$with_gsl],
+ [no], [have_gsl=no],
+ [yes], [DX_CHECK_GSL([1.0], [have_gsl=yes])],
+ [DX_CHECK_GSL([1.0], [have_gsl=yes], [have_gsl=no])])