[OCaml] Clear cross-target test deps when building out-of-tree

[mgorny]

Summary

Clear cross-target test dependencies when using LLVM_OCAML_OUT_OF_TREE,
in order to make it possible to run check-llvm-bindings-ocaml without
rebuilding the whole LLVM.

llvm/trunk/test/CMakeLists.txt

 if(TARGET llvm-go)
   set(LLVM_TEST_DEPENDS ${LLVM_TEST_DEPENDS} llvm-go)
 endif()
 
 if(TARGET LTO)
   set(LLVM_TEST_DEPENDS ${LLVM_TEST_DEPENDS} LTO)
 endif()
 
+if(LLVM_BUILD_EXAMPLES)
+  list(APPEND LLVM_TEST_DEPENDS
+    Kaleidoscope-Ch3
+    Kaleidoscope-Ch4
+    Kaleidoscope-Ch5
+    Kaleidoscope-Ch6
+    Kaleidoscope-Ch7
+    )
+endif()
+
 if(TARGET ocaml_llvm)
+  # Clear all non-OCaml cross-target dependencies when building out-of-tree.
+  if(LLVM_OCAML_OUT_OF_TREE)
+    set(LLVM_TEST_DEPENDS)
+  endif()
+
   set(LLVM_TEST_DEPENDS ${LLVM_TEST_DEPENDS}
           ocaml_llvm
           ocaml_llvm_all_backends
           ocaml_llvm_analysis
           ocaml_llvm_bitreader
           ocaml_llvm_bitwriter
           ocaml_llvm_executionengine
           ocaml_llvm_irreader
           ocaml_llvm_linker
           ocaml_llvm_target
           ocaml_llvm_ipo
           ocaml_llvm_passmgr_builder
           ocaml_llvm_scalar_opts
           ocaml_llvm_transform_utils
           ocaml_llvm_vectorize
         )
 endif()
 
-if(LLVM_BUILD_EXAMPLES)
-  list(APPEND LLVM_TEST_DEPENDS
-    Kaleidoscope-Ch3
-    Kaleidoscope-Ch4
-    Kaleidoscope-Ch5
-    Kaleidoscope-Ch6
-    Kaleidoscope-Ch7
-    )
-endif()
-
 add_custom_target(llvm-test-depends DEPENDS ${LLVM_TEST_DEPENDS})
 set_target_properties(llvm-test-depends PROPERTIES FOLDER "Tests")
 
 add_lit_testsuite(check-llvm "Running the LLVM regression tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   PARAMS llvm_site_config=${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
          llvm_unit_site_config=${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg
   DEPENDS ${LLVM_TEST_DEPENDS}