Export headers from libpiex
am: b57a64fc86

Change-Id: I5ce759878936a92261ff6e89f790d46d30045aaf
diff --git a/Android.bp b/Android.bp
index 8e7ec9e..894bf3b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -31,6 +31,7 @@
         "src/tiff_parser.cc",
         "src/piex.cc",
     ],
+    export_include_dirs: ["."],
     static_libs: [
         "libbinary_parse",
         "libimage_type_recognition",