Disable the invalid pointer test on FreeBSD

FreeBSD segfaults on invalid pointers passed to getcwd because it throbs the
address passed in in libc, whereas NetBSD just passes the information off to
the syscall, which allows the kernel to return EFAULT on bad pointers.

In collaboration with: pho
Sponsored by: EMC / Isilon Storage Division

contrib/netbsd-tests/lib/libc/gen/t_getcwd.c

@@ -56,10 +56,12 @@ ATF_TC_BODY(getcwd_err, tc)
 	ATF_REQUIRE(getcwd(buf, 0) == NULL);
 	ATF_REQUIRE(errno == EINVAL);
 
+#if defined(__NetBSD__)
 	errno = 0;
 
 	ATF_REQUIRE(getcwd((void *)-1, sizeof(buf)) == NULL);
 	ATF_REQUIRE(errno == EFAULT);
+#endif
 }
 
 ATF_TC(getcwd_fts);