diff --git a/cpp/analytics/BUILD b/cpp/analytics/BUILD
index 8b701d47..e72aeea4 100644
--- a/cpp/analytics/BUILD
+++ b/cpp/analytics/BUILD
@@ -22,6 +22,7 @@ cc_library(
         "analytics_recorder.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//core:__subpackages__",
         "//proto/analytics:__subpackages__",
diff --git a/cpp/core/BUILD b/cpp/core/BUILD
index 65ba013c..1c3a26c1 100644
--- a/cpp/core/BUILD
+++ b/cpp/core/BUILD
@@ -22,6 +22,7 @@ cc_library(
         "core.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
         "//third_party/nearby_connections/windows:__subpackages__",
@@ -53,6 +54,7 @@ cc_library(
         "strategy.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
         "//analytics:__subpackages__",
diff --git a/cpp/core/internal/BUILD b/cpp/core/internal/BUILD
index 4c59d0f0..9247f02e 100644
--- a/cpp/core/internal/BUILD
+++ b/cpp/core/internal/BUILD
@@ -84,6 +84,7 @@ cc_library(
         "wifi_lan_service_info.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//core:__pkg__",
         "//core/internal/fuzzers:__pkg__",
diff --git a/cpp/core/internal/fuzzers/BUILD b/cpp/core/internal/fuzzers/BUILD
index 56175c5b..f43a02c5 100644
--- a/cpp/core/internal/fuzzers/BUILD
+++ b/cpp/core/internal/fuzzers/BUILD
@@ -19,6 +19,7 @@ cc_fuzz_target(
     name = "offline_frames_fuzzer",
     srcs = ["offline_frames_fuzzer.cc"],
     componentid = 148515,
+    copts = ["-DCORE_ADAPTER_DLL"],
     deps = [
         "//security/fuzzing/blaze:default_init_google_for_cc_fuzz_target",
         "//core/internal",
diff --git a/cpp/core/internal/mediums/ble_v2/BUILD b/cpp/core/internal/mediums/ble_v2/BUILD
index ba9b94e4..2e6685fd 100644
--- a/cpp/core/internal/mediums/ble_v2/BUILD
+++ b/cpp/core/internal/mediums/ble_v2/BUILD
@@ -30,6 +30,7 @@ cc_library(
         "discovered_peripheral_callback.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//core/internal:__subpackages__",
     ],
diff --git a/cpp/core/internal/mediums/webrtc/BUILD b/cpp/core/internal/mediums/webrtc/BUILD
index fedff28f..52f7fc30 100644
--- a/cpp/core/internal/mediums/webrtc/BUILD
+++ b/cpp/core/internal/mediums/webrtc/BUILD
@@ -32,6 +32,7 @@ cc_library(
         "webrtc_socket_wrapper.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//core/internal:__subpackages__",
     ],
diff --git a/cpp/platform/base/BUILD b/cpp/platform/base/BUILD
index 1bd35792..fa8f5386 100644
--- a/cpp/platform/base/BUILD
+++ b/cpp/platform/base/BUILD
@@ -41,6 +41,7 @@ cc_library(
         "types.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
         "//analytics:__subpackages__",
diff --git a/cpp/platform/impl/windows/BUILD b/cpp/platform/impl/windows/BUILD
index a62ca186..8bd81cb8 100644
--- a/cpp/platform/impl/windows/BUILD
+++ b/cpp/platform/impl/windows/BUILD
@@ -109,25 +109,8 @@ cc_library(
         "wifi_lan_nsd.cc",
         "wifi_lan_socket.cc",
     ],
-    hdrs = [
-        "bluetooth_classic.h",
-        "bluetooth_classic_device.h",
-        "bluetooth_classic_medium.h",
-        "bluetooth_classic_server_socket.h",
-        "bluetooth_classic_socket.h",
-        "condition_variable.h",
-        "executor.h",
-        "mutex.h",
-        "runner.h",
-        "scheduled_executor.h",
-        "submittable_executor.h",
-        "thread_pool.h",
-        "wifi_lan.h",
-    ],
     compatible_with = ["//buildenv/target:non_prod"],
-    copts = [
-        "-Ithird_party/nearby_connections/cpp/platform/impl/windows/generated",
-    ],
+    copts = ["-Ithird_party/nearby_connections/cpp/platform/impl/windows/generated"],
     visibility = [
         "//third_party/nearby_connections/windows:__subpackages__",
     ],
@@ -176,7 +159,7 @@ cc_test(
         "scheduled_executor_test.cc",
         "submittable_executor_test.cc",
     ],
-    copts = ["-Iplatform/impl/windows/generated"],
+    copts = ["-Iplatform/impl/windows/generated -DCORE_ADAPTER_DLL"],
     deps = [
         ":comm",
         ":crypto",
diff --git a/cpp/platform/public/BUILD b/cpp/platform/public/BUILD
index f6e1a779..3d36102d 100644
--- a/cpp/platform/public/BUILD
+++ b/cpp/platform/public/BUILD
@@ -85,6 +85,7 @@ cc_library(
         "wifi_lan.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
         "//core:__subpackages__",
@@ -110,6 +111,7 @@ cc_library(
         "logging.h",
     ],
     compatible_with = ["//buildenv/target:non_prod"],
+    copts = ["-DCORE_ADAPTER_DLL"],
     visibility = [
         "//analytics:__subpackages__",
         "//core:__subpackages__",
@@ -144,6 +146,7 @@ cc_test(
         "single_thread_executor_test.cc",
         "wifi_lan_test.cc",
     ],
+    copts = ["-DCORE_ADAPTER_DLL"],
     shard_count = 16,
     deps = [
         ":comm",
diff --git a/windows/BUILD b/windows/BUILD
index 37ddcf90..1fe8ad6d 100644
--- a/windows/BUILD
+++ b/windows/BUILD
@@ -11,7 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 load("//third_party/msvc:build_windows.bzl", "cc_windows_dll")
 
 licenses(["notice"])
@@ -21,7 +20,7 @@ cc_windows_dll(
     name = "core_adapter",
     srcs = ["core_adapter.cc"],
     hdrs = ["core_adapter.h"],
-    copts = ["-DCORE_ADAPTER_BUILD_DLL"],
+    copts = ["-DCORE_ADAPTER_BUILD_DLL -DCOMPILING_CORE"],
     defines = ["CORE_ADAPTER_DLL"],
     tags = ["windows-dll"],
     deps = [