hal: Add separate backend for headset-mic

Add separate backend for headset-mic
for concurrent record usecase.

Change-Id: Iba26751eb51c00a62016a47e0d3c726b155cf169
diff --git a/hal/Android.mk b/hal/Android.mk
index d9d45e7..44a957b 100644
--- a/hal/Android.mk
+++ b/hal/Android.mk
@@ -330,6 +330,10 @@
     LOCAL_SRC_FILES += audio_extn/compress_in.c
 endif
 
+ifeq ($(strip $(AUDIO_FEATURE_ENABLED_CONCURRENT_CAPTURE)),true)
+    LOCAL_CFLAGS += -DCONCURRENT_CAPTURE_ENABLED
+endif
+
 ifeq ($(strip $(BOARD_SUPPORTS_QAHW)),true)
     LOCAL_CFLAGS += -DAUDIO_HW_EXTN_API_ENABLED
     LOCAL_SRC_FILES += audio_hw_extn_api.c