Preserve the source directory tree in the RPM BUILD directory

Previously, there was a risk of filename collisions, since all data files were flattened into the BUILD directory.

Closes #4747.

PiperOrigin-RevId: 187870196

tools/build_defs/pkg/make_rpm.py

diff --git a/tools/build_defs/pkg/make_rpm.py b/tools/build_defs/pkg/make_rpm.py
index 0b3e59b..fd4caee 100644
--- a/tools/build_defs/pkg/make_rpm.py
+++ b/tools/build_defs/pkg/make_rpm.py
@@ -182,7 +182,10 @@
 
     # Copy the files.
     for f in self.files:
-      shutil.copy(os.path.join(original_dir, f), RpmBuilder.BUILD_DIR)
+      dst_dir = os.path.join(RpmBuilder.BUILD_DIR, os.path.dirname(f))
+      if not os.path.exists(dst_dir):
+        os.makedirs(dst_dir, 0o777)
+      shutil.copy(os.path.join(original_dir, f), dst_dir)
 
     # Copy the spec file, updating with the correct version.
     spec_origin = os.path.join(original_dir, spec_file)