Use a compile and run test for lchown() to satisfy clang++.

Use a compile and run test for lchown() to satisfy clang++.

For glibc, previous reports were that some functions (such as lchown())
are present in libc, but are unimplemented.  That is, they always fail
and set errno=ENOSYS.  Unfortunately, the stub test doesn't work under
clang++.  Thus use a compile and run test.  This should be more reliable.