compare-flags: Don't rely on encoding flag of subprocess.check_output

Apparently it isn't supported by some slightly older Python versions.

1 files changed, 2 insertions, 3 deletions

diff --git a/docs/users_guide/compare-flags.py b/docs/users_guide/compare-flags.py
index bfb8da65cf..d18abb4d7a 100755
--- a/docs/users_guide/compare-flags.py
+++ b/docs/users_guide/compare-flags.py
@@ -48,10 +48,9 @@ def read_documented_flags(doc_flags) -> Set[str]:
             if line != ''}
 
 def read_ghc_flags(ghc_path: str) -> Set[str]:
-    ghc_output = subprocess.check_output([ghc_path, '--show-options'],
-                                         encoding='UTF-8')
+    ghc_output = subprocess.check_output([ghc_path, '--show-options'])
     return {flag
-            for flag in ghc_output.split('\n')
+            for flag in ghc_output.decode('UTF-8').split('\n')
             if not expected_undocumented(flag)
             if flag != ''}