Mark angler as containing duplicate build rules

Bug: 77611511
Test: with https://android-review.googlesource.com/c/platform/build/soong/+/709015
Change-Id: I201f3adbfa4e1148bbde79fab6a02340e7a82914
diff --git a/BoardConfig.mk b/BoardConfig.mk
index f412575..5b0d11a 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -14,6 +14,8 @@
 # limitations under the License.
 #
 
+BUILD_BROKEN_DUP_RULES := true
+
 TARGET_BOARD_PLATFORM := msm8994
 TARGET_BOOTLOADER_BOARD_NAME := angler