versioner: introduce.

Add a clang-based tool to inspect header availability attributes and
verify them against the NDK platform definitions.

Bug: http://b/28178111
Change-Id: I1bb1925a620e98cc9606cb5a3360b1224c700bd0
diff --git a/tools/versioner/tests/multiple_decl/run.sh b/tools/versioner/tests/multiple_decl/run.sh
new file mode 100644
index 0000000..d26ab70
--- /dev/null
+++ b/tools/versioner/tests/multiple_decl/run.sh
@@ -0,0 +1 @@
+versioner headers dependencies -p platforms -r arm -a 9