Add vfp support on ARM. Patch from John Jozwiak.

src/platform.h

Index: src/platform.h
===================================================================
--- src/platform.h	(revision 3208)
+++ src/platform.h	(working copy)
@@ -250,6 +250,9 @@
   // Returns the double constant NAN
   static double nan_value();
 
+  // Support runtime detection of VFP3 on linux platforms.
+  static bool fgrep_vfp(const char * file_name, const char * string);
+
   // Returns the activation frame alignment constraint or zero if
   // the platform doesn't care. Guaranteed to be a power of two.
   static int ActivationFrameAlignment();