Add test to show bug with expanding %{ocaml:..} forms

Signed-off-by: Rudi Grinberg <rudi.grinberg@gmail.com>

test/blackbox-tests/dune.inc

@@ -436,6 +436,14 @@
    test-cases/null-dep
    (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
 
+(alias
+ (name ocaml-config-macro)
+ (deps (package dune) (source_tree test-cases/ocaml-config-macro))
+ (action
+  (chdir
+   test-cases/ocaml-config-macro
+   (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
+
 (alias
  (name ocaml-syntax)
  (deps (package dune) (source_tree test-cases/ocaml-syntax))
@@ -698,6 +706,7 @@
   (alias multiple-private-libs)
   (alias no-installable-mode)
   (alias null-dep)
+  (alias ocaml-config-macro)
   (alias ocaml-syntax)
   (alias ocamldep-multi-stanzas)
   (alias odoc)
@@ -773,6 +782,7 @@
   (alias misc)
   (alias no-installable-mode)
   (alias null-dep)
+  (alias ocaml-config-macro)
   (alias ocaml-syntax)
   (alias ocamldep-multi-stanzas)
   (alias output-obj)

test/blackbox-tests/test-cases/ocaml-config-macro/dune

@@ -0,0 +1,3 @@
+(rule
+ (targets x)
+ (action (with-stdout-to %{targets} (echo %{ocaml-config:system}))))

test/blackbox-tests/test-cases/ocaml-config-macro/dune-project

@@ -0,0 +1 @@
+(lang dune 1.0)

test/blackbox-tests/test-cases/ocaml-config-macro/run.t

@@ -0,0 +1,7 @@
+%{ocaml-config:...} macros should be available. we don't print anything because
+the values are all platform specific.
+
+  $ dune build
+  File "dune", line 3, characters 41-61:
+  Error: Unknown form: %{ocaml-config:system}
+  [1]