init: enable C++17

Test: Boot bullhead
Change-Id: I40961ff765461e8aef211d27158ffb7c4be76493
diff --git a/init/Android.mk b/init/Android.mk
index 1a47eb4..2a1ad9c 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -17,6 +17,7 @@
     -Wall -Wextra \
     -Wno-unused-parameter \
     -Werror \
+    -std=gnu++1z \
 
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