Fix import/export annotations for v8 targets that are always static

test/unittests/unittests.gyp

Index: test/unittests/unittests.gyp
diff --git a/test/unittests/unittests.gyp b/test/unittests/unittests.gyp
index c7deada92fbcd553c1eab6957307852a2a46fcbf..b5759a45f20e98a815c25bbe6bffc890acf6ffb6 100644
--- a/test/unittests/unittests.gyp
+++ b/test/unittests/unittests.gyp
@@ -230,6 +230,7 @@
           # compiler-unittests can't be built against a shared library, so we
           # need to depend on the underlying static target in that case.
           'dependencies': ['../../src/v8.gyp:v8_maybe_snapshot'],
+          'defines': [ 'BUILDING_V8_SHARED', ]
         }, {
           'dependencies': ['../../src/v8.gyp:v8'],
         }],