[clang] [clang][python] Don't add check-clang-python to check-all if cross-compiling (PR #111657)

[Alex Bradbury via cfe-commits]

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@@ -47,6 +47,14 @@ if(${LLVM_NATIVE_ARCH} MATCHES "^(AArch64|Hexagon|Sparc|SystemZ)$")
   set(RUN_PYTHON_TESTS FALSE)
 endif()
 
+# Tests will fail if cross-compiling for a different target, as tests will try
+# to use the host Python3_EXECUTABLE and make FFI calls to functions in target
+# libraries.
+if(CMAKE_CROSS_COMPILING)
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asb wrote:

Yes, I'm trying for now to just make changes that remove the small bits of friction for cross-compiling and then testing using qemu-user as a litmus test rather  than (for now) make it "officially supported".

It is indeed correct that there's no problem with the regular tests in clang/test (other than clang/test/Driver/env.c if you need QEMU_LD_PREFIX passed through, as the test strips envvars - but of course for the lit-orchestrated tests we already have a mechanism to skip tests downstream by configuring the LIT_ARGS).

https://github.com/llvm/llvm-project/pull/111657