Issue #21311: Avoid exception in _osx_support with non-standard compiler

configurations.  Patch by John Szakmeister.

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')
 

Misc/ACKS

@@ -1280,6 +1280,7 @@ Andrew Svetlov
 Paul Swartz
 Thenault Sylvain
 Péter Szabó
+John Szakmeister
 Amir Szekely
 Arfrever Frehtes Taifersar Arahesis
 Hideaki Takahashi

Misc/NEWS

@@ -271,6 +271,9 @@ Library
   (Original patches by Hirokazu Yamamoto and Amaury Forgeot d'Arc, with
   suggested wording by David Gutteridge)
 
+- Issue #21311: Avoid exception in _osx_support with non-standard compiler
+  configurations.  Patch by John Szakmeister.
+
 Tools/Demos
 -----------