Don't compile `__data_end` on clang 9.0.

tests/compile-only/addresses.c

@@ -2,16 +2,20 @@
 #include <limits.h>
 
 extern void __dso_handle;
+#if !defined(__clang_major__) || __clang_major__ >= 10
 extern void __data_end;
 extern void __global_base;
 extern void __heap_base;
+#endif
 
 int main(int argc, char *argv[]) {
     printf("NULL=%p\n", NULL);
     printf("__dso_handle=%p\n", &__dso_handle);
+#if !defined(__clang_major__) || __clang_major__ >= 10
     printf("__data_end=%p\n", &__data_end);
     printf("__global_base=%p\n", &__global_base);
     printf("__heap_base=%p\n", &__heap_base);
+#endif
     printf("__builtin_frame_address(0)=%p\n", __builtin_frame_address(0));
     printf("__builtin_alloca(0)=%p\n", __builtin_alloca(0));
     printf("__builtin_wasm_memory_size(0)=%p\n", (void *)(__builtin_wasm_memory_size(0) * PAGE_SIZE));