Fix a missing path issue causing Python traceback.
A path was missing from a call to os.path.relpath when handling rpaths.
Fix this by assuming empty target directory means build root.
@@ -763,6 +763,10 @@ class Compiler:
# directory. This breaks reproducible builds.
rel_rpaths = []
for p in rpath_paths:
+ # p can be an empty string for build_dir (relative path), but
+ # os.path.relpath() below won't like that.
+ if p == '':
+ p = build_dir
if p == from_dir:
relative = '' # relpath errors out in this case
else:
