Declare dependency on android_filesystem_config.h

android_filesystem_config.h comes from a directory outside bionic/libc
so it can't be referenced directly, add it as a source file through
a filegroup module.

Bug: 34283327
Test: builds
Test: libc rebuilds after touch system/core/include/private/android_filesystem_config.h
Change-Id: I90f6b7b25b70842b8619d558074449f13e6e6b03
diff --git a/libc/Android.bp b/libc/Android.bp
index 33fa447..4df94a0 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1203,9 +1203,10 @@
 
 genrule {
     name: "generated_android_ids",
-    out: [ "generated_android_ids.h" ],
-    tool_files: [ "fs_config_generator.py" ],
-    cmd: "$(location fs_config_generator.py) aidarray system/core/include/private/android_filesystem_config.h > $(out)",
+    out: ["generated_android_ids.h"],
+    srcs: [":android_filesystem_config_header"],
+    tool_files: ["fs_config_generator.py"],
+    cmd: "$(location fs_config_generator.py) aidarray $(in) > $(out)",
 }
 
 // ========================================================