Remove a duplicate declaration, improve check-symbols-glibc.py.

Change-Id: I97a98dfc8acaa93172386b4475487a05a35a9337
diff --git a/libc/dns/include/resolv_netid.h b/libc/dns/include/resolv_netid.h
index 266193a..7182ca6 100644
--- a/libc/dns/include/resolv_netid.h
+++ b/libc/dns/include/resolv_netid.h
@@ -101,9 +101,6 @@
 int android_getnameinfofornet(const struct sockaddr *, socklen_t, char *, size_t, char *, size_t, int, unsigned, unsigned) __LIBC_HIDDEN__;
 FILE* android_open_proxy(void) __LIBC_HIDDEN__;
 
-/* delete the cache associated with a certain network */
-extern void _resolv_delete_cache_for_net(unsigned netid);
-
 __END_DECLS
 
 #endif /* _RESOLV_NETID_H */
diff --git a/libc/tools/check-symbols-glibc.py b/libc/tools/check-symbols-glibc.py
index 43531c0..3185c81 100755
--- a/libc/tools/check-symbols-glibc.py
+++ b/libc/tools/check-symbols-glibc.py
@@ -108,15 +108,16 @@
   '__strlen_chk',
   '__strncpy_chk2',
   '__strrchr_chk',
-  '__umask_chk'
+  '__umask_chk',
   '__write_chk',
 ])
-# Some symbols are used to implement public macros.
+# Some symbols are used to implement public functions/macros.
 macro_stuff = set([
   '__assert2',
   '__errno',
   '__fe_dfl_env',
   '__get_h_errno',
+  '__gnu_strerror_r',
   '__fpclassifyd',
   '__isfinite',
   '__isfinitef',
@@ -132,7 +133,8 @@
 linux_stuff = set([
   'getauxval',
   'gettid',
-  'tgkill'
+  'pthread_gettid_np',
+  'tgkill',
 ])
 # Some standard stuff isn't yet in the versions of glibc we're using.
 std_stuff = set([
@@ -168,6 +170,7 @@
 libresolv_stuff = set([
   '__res_send_setqhook',
   '__res_send_setrhook',
+  '_resolv_delete_cache_for_net',
   '_resolv_flush_cache_for_net',
   '_resolv_set_nameservers_for_net',
   'dn_expand',