Camera: add static assertion for camera_metadata

Make sure no one updates these structs in the future.
Treble will allow framework and HAL targeting different
copy of libcamera_metadata, so make sure we don't update
these structs and cause mismatch.

Test: compile (as this is static check)
Bug: 37287148
Change-Id: Ibfc6d710e97e276a9d7eea1ceee1736f75f9a056
diff --git a/camera/Android.bp b/camera/Android.bp
index 4a2c96f..ba31c56 100644
--- a/camera/Android.bp
+++ b/camera/Android.bp
@@ -19,7 +19,7 @@
         "-Wextra",
         "-Werror",
         "-fvisibility=hidden",
-        "-std=c99",
+        "-std=c11",
     ],
 
     product_variables: {