firefox does not build on pkgsrc HEAD

[Sergio de Almeida Lenzi <lenzi.sergio%gmail.com@localhost>]

version 47 of firefox (www/firefox) does not build becase

it needs nexttowardf(3) that is not available on NetBSD6 or 7

patch in the attach resolv the problem

$NetBSD$

--- gfx/skia/skia/src/core/SkScaleToSides.h.orig	2016-10-13 12:07:53.000000000 +0000
+++ gfx/skia/skia/src/core/SkScaleToSides.h
@@ -49,7 +49,7 @@ public:
             // Note: nexttowardf is a c99 call and should be std::nexttoward, but this is not
             // implemented in the ARM compiler.
             if ((double)newMaxRadius + (double)newMinRadius > limit) {
-                newMaxRadius = nexttowardf(newMaxRadius, 0.0);
+                newMaxRadius = nexttoward((float)newMaxRadius, 0.0);
             }
             *maxRadius = newMaxRadius;
         }