diff --git a/build-buildroot b/build-buildroot
index 3f43265..00b97f0 100755
--- a/build-buildroot
+++ b/build-buildroot
@@ -153,7 +153,7 @@ files on the root filesystem.
             extra_make_args
             ,
             out_file=os.path.join(self.env['buildroot_build_dir'], self.env['repo_short_id'] + '.log'),
-            delete_env=['LD_LIBRARY_PATH'],
+            delete_env=['LD_LIBRARY_PATH', 'PERL_MM_OPT'],
             cwd=self.env['buildroot_source_dir'],
         )
         # Create the qcow2 from ext2.