[clang] [test] Disable Python binding tests w/ LLVM_ENABLE_PIC=OFF

[mgorny]

Summary

Disable Python binding tests when LLVM_ENABLE_PIC is disabled,
as libclang.so is not being built in that case. Reported by Nico Weber.

@thakis, could you test it, please?

[thakis]

Thanks!

I can't easily test this since only some of our bots see this and I don't have a Linux box at hand, but it looks like it should work and I can verify on the bots once this is in :)

bindings/python/tests/CMakeLists.txt

 # Test target to run Python test suite from main build.
 
 add_custom_target(check-clang-python
     COMMAND ${CMAKE_COMMAND} -E env
             CLANG_LIBRARY_PATH=$<TARGET_FILE_DIR:libclang>
             ${PYTHON_EXECUTABLE} -m unittest discover
     DEPENDS libclang
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/..)
 
 set(RUN_PYTHON_TESTS TRUE)
 set_target_properties(check-clang-python PROPERTIES FOLDER "Clang tests")
 
+# Tests require libclang.so which is only built with LLVM_ENABLE_PIC=ON
+if(NOT LLVM_ENABLE_PIC)
+  set(RUN_PYTHON_TESTS FALSE)
+endif()
+
 # Do not try to run if libclang was built with ASan because
 # the sanitizer library will likely be loaded too late to perform
 # interception and will then fail.
 # We could use LD_PRELOAD/DYLD_INSERT_LIBRARIES but this isn't
 # portable so its easier just to not run the tests when building
 # with ASan.
 list(FIND LLVM_USE_SANITIZER "Address" LLVM_USE_ASAN_INDEX)
 if(NOT LLVM_USE_ASAN_INDEX EQUAL -1)