3 files changed, 5 insertions, 1 deletions
diff --git a/Lib/_osx_support.py b/Lib/_osx_support.py
index 40fc78b..b6eac5f 100644
--- a/Lib/_osx_support.py
+++ b/Lib/_osx_support.py
@@ -182,7 +182,7 @@ def _find_appropriate_compiler(_config_vars):
         # Compiler is GCC, check if it is LLVM-GCC
         data = _read_output("'%s' --version"
                              % (cc.replace("'", "'\"'\"'"),))
-        if 'llvm-gcc' in data:
+        if data and 'llvm-gcc' in data:
             # Found LLVM-GCC, fall back to clang
             cc = _find_build_tool('clang')
 
diff --git a/Misc/ACKS b/Misc/ACKS
index 40f7cbe..65d1adb 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1281,6 +1281,7 @@ Andrew Svetlov
 Paul Swartz
 Thenault Sylvain
 Péter Szabó
+John Szakmeister
 Amir Szekely
 Arfrever Frehtes Taifersar Arahesis
 Hideaki Takahashi
diff --git a/Misc/NEWS b/Misc/NEWS
index 3e121af..1b5ac6c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -165,6 +165,9 @@ Library
 - asyncio: Add gi_{frame,running,code} properties to CoroWrapper
   (upstream issue #163).
 
+- Issue #21311: Avoid exception in _osx_support with non-standard compiler
+  configurations.  Patch by John Szakmeister.
+
 Extension Modules
 -----------------