Use libgtest_prod_headers.

Test: builds
Bug: 185916167
Change-Id: Ifdb71aa9e6e9eeadd4d7c9cb4850832650dd12e8
diff --git a/modules/camera/3_4/Android.mk b/modules/camera/3_4/Android.mk
index 0a11f68..de584e3 100644
--- a/modules/camera/3_4/Android.mk
+++ b/modules/camera/3_4/Android.mk
@@ -91,9 +91,8 @@
 LOCAL_MODULE_RELATIVE_PATH := hw
 LOCAL_CFLAGS += $(v4l2_cflags)
 LOCAL_SHARED_LIBRARIES := $(v4l2_shared_libs)
-LOCAL_STATIC_LIBRARIES := \
-  libgtest_prod \
-  $(v4l2_static_libs) \
+LOCAL_HEADER_LIBRARIES := libgtest_prod_headers
+LOCAL_STATIC_LIBRARIES := $(v4l2_static_libs)
 
 LOCAL_C_INCLUDES += $(v4l2_c_includes)
 LOCAL_SRC_FILES := $(v4l2_src_files)