Add a new rule to generate the custom grpc interfaces

Soong was reading the content of the symbolic link instead of the
target of it. Thus instead of reading the content of protoc-gen-custom_grpc it
was reading the content of protoc-gen-custom_grpc.py, which was a
symbolic link to protoc-gen-custom_grpc.

Bug: 245747653
Test: manual

Ignore-AOSP-First: cherry-pick
Change-Id: I37c0af2ffa6803ad1114fccbff4fdcf6914c54c1
Merged-In: I37c0af2ffa6803ad1114fccbff4fdcf6914c54c1
diff --git a/Android.bp b/Android.bp
index 0239d6a..c15b5c7 100644
--- a/Android.bp
+++ b/Android.bp
@@ -17,10 +17,17 @@
     ],
 }
 
+genrule {
+    name: "protoc-gen-mmi2grpc-python-src-interfaces",
+    srcs: ["python/_build/protoc-gen-custom_grpc"],
+    cmd: "cp $(in) $(out)",
+    out: ["protoc-gen-custom_grpc.py"],
+}
+
 python_binary_host {
     name: "protoc-gen-custom_grpc",
-    main: "python/_build/protoc-gen-custom_grpc.py",
-    srcs: ["python/_build/protoc-gen-custom_grpc.py"],
+    main: "protoc-gen-custom_grpc.py",
+    srcs: [":protoc-gen-mmi2grpc-python-src-interfaces"],
     libs: ["libprotobuf-python"],
 }
 
diff --git a/python/_build/protoc-gen-custom_grpc.py b/python/_build/protoc-gen-custom_grpc.py
deleted file mode 120000
index 88d6a75..0000000
--- a/python/_build/protoc-gen-custom_grpc.py
+++ /dev/null
@@ -1 +0,0 @@
-protoc-gen-custom_grpc
\ No newline at end of file