[libcxx-commits] [libcxx] [libc++] Fixes lit portability issues. (PR #72435)

[Stephan T. Lavavej via libcxx-commits]

================
@@ -29,7 +29,13 @@ def appendToSubstitution(substitutions, key, value):
     return [(k, v + " " + value) if k == key else (k, v) for (k, v) in substitutions]
 
 
-std = getSubstitution("%{cxx_std}", config)
+# External users of the LLVM test suite might not have set the substitutions.
+std = ""
+try:
+    std = getSubstitution("%{cxx_std}", config)
+except:
+    pass
----------------
StephanTLavavej wrote:

Ok, I think I can fix this on the microsoft/STL side! If I add

```python
config.substitutions.append(('%{cxx_std}', ''))
```

to our `tests\std\lit.site.cfg.in`, `tests\tr1\lit.site.cfg.in`, `tests\libcxx\lit.site.cfg.in`, that unblocks the test pass.

https://github.com/llvm/llvm-project/pull/72435