Remove <private/bsd_sys_param.h>.

It's hardly used, and the two most interesting users are clearer with
modern alignof() anyway.

Bug: 373789390
Change-Id: I52368ab372ee3afd4ed2dd8e373ff0223d59db0e
diff --git a/libc/dns/net/sethostent.c b/libc/dns/net/sethostent.c
index 5c4bdb5..8ea4315 100644
--- a/libc/dns/net/sethostent.c
+++ b/libc/dns/net/sethostent.c
@@ -198,7 +198,7 @@
 				HENT_SCOPY(aliases[anum], hp->h_aliases[anum],
 				    ptr, len);
 			}
-			ptr = (void *)ALIGN(ptr);
+			ptr = __builtin_align_up(ptr, sizeof(uintptr_t));
 			if ((size_t)(ptr - buf) >= info->buflen)
 				goto nospc;
 		}