Get ourselves some clang-format.

These are the same rules used by system/core/.  We'll apply it to
existing code in a future CL.

Test: none
Bug: 67041047
Change-Id: I407581a9ba155aea87ac87f231f5269f7c444a2e
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
new file mode 100644
index 0000000..c8dbf77
--- /dev/null
+++ b/PREUPLOAD.cfg
@@ -0,0 +1,5 @@
+[Builtin Hooks]
+clang_format = true
+
+[Builtin Hooks Options]
+clang_format = --commit ${PREUPLOAD_COMMIT} --style file --extensions c,h,cc,cpp