Define MAXHOSTNAMELEN explicitly in source files.

Bug: 19093777
Bug: 19092844
Change-Id: I0778507ca2d5c008abb9a6d6315d0909263a8817
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index 2efd455..8aba998 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -118,10 +118,8 @@
 # the generated files.
 #
 kernel_ignored_macros = set(
-        [ "MAXHOSTNAMELEN",  # for some reason, Linux defines it to 64
-                             # while most of the BSD code expects this to be 256
-                             # so ignore the kernel-provided definition and
-                             # define it in the Bionic headers instead
+        [
+
         ]
     )