cmake HAVE_BUILTIN_THREAD_POINTER examples

Lewuathe/mlir-hello thirdparty/llvm-project/llvm/cmake/config-ix.cmake :104

check_c_source_compiles("
        #if __has_attribute(used)
        #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
        #else
        #define LLVM_ATTRIBUTE_USED
        #endif
        LLVM_ATTRIBUTE_USED void *foo() {
          return __builtin_thread_pointer();
        }
        int main(void) { return 0; }"
        HAVE_BUILTIN_THREAD_POINTER)

root-project/root interpreter/llvm-project/llvm/cmake/config-ix.cmake :67

check_c_source_compiles("
        #if __has_attribute(used)
        #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
        #else
        #define LLVM_ATTRIBUTE_USED
        #endif
        LLVM_ATTRIBUTE_USED void *foo() {
          return __builtin_thread_pointer();
        }
        int main(void) { return 0; }"
        HAVE_BUILTIN_THREAD_POINTER)