Remove -fvisibility=hidden from dns code

We no longer need it because version script controls
list of symbols we export.

This also fixes mips/mips64 builds.

Bug: http://b/24767418
Change-Id: I61c504665fc0349275384596d375155991743e05
diff --git a/libc/Android.bp b/libc/Android.bp
index c5a513c..9c521d1 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -195,7 +195,6 @@
     cflags: [
         "-DANDROID_CHANGES",
         "-DINET6",
-        "-fvisibility=hidden",
         "-Wno-unused-parameter",
         "-include netbsd-compat.h",
     ],
diff --git a/libc/Android.mk b/libc/Android.mk
index 374ffa6..2814e6b 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -750,7 +750,6 @@
     $(libc_common_cflags) \
     -DANDROID_CHANGES \
     -DINET6 \
-    -fvisibility=hidden \
     -Wno-unused-parameter \
     -include netbsd-compat.h \