Add se_build_files module

se_build_files module globs given srcs from sepolicy directories and
acts as a filegroup with the following tags, which can be used to build
system side policy files.

- plat
- plat_public
- system_ext
- system_ext_public
- product
- product_public
- reqd_mask

se_build_files module acts like the build_policy macro in Android.mk.
Normal genrule module can't easily handle that, because both file order
and directory order matter.

Support for vendor/odm is to be added in the future.

Bug: 33691272
Test: inspect se_build_files with above tags and compare it to ninja
Change-Id: Id7c57b01c78fc14ac5e8eeeb074a6fc21d271e84
diff --git a/Android.bp b/Android.bp
index 8fa57ca..aca6e40 100644
--- a/Android.bp
+++ b/Android.bp
@@ -735,3 +735,30 @@
     relative_install_path: "selinux",
     installable: false,
 }
+
+se_build_files {
+    name: "se_build_files",
+    srcs: [
+        "security_classes",
+        "initial_sids",
+        "access_vectors",
+        "global_macros",
+        "neverallow_macros",
+        "mls_macros",
+        "mls_decl",
+        "mls",
+        "policy_capabilities",
+        "te_macros",
+        "attributes",
+        "ioctl_defines",
+        "ioctl_macros",
+        "*.te",
+        "roles_decl",
+        "roles",
+        "users",
+        "initial_sid_contexts",
+        "fs_use",
+        "genfs_contexts",
+        "port_contexts",
+    ],
+}