Changes to get rid of dependency on openssl in the dart VM.

vm/raw_object.h

Index: vm/raw_object.h
===================================================================
--- vm/raw_object.h	(revision 4707)
+++ vm/raw_object.h	(working copy)
@@ -834,12 +834,19 @@
 class RawBigint : public RawInteger {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Bigint);
 
-  // Note that the structure is not necessarily valid unless tweaked
-  // by Bigint::BNAddr().
-  BIGNUM bn_;
+  // Actual length at the time of allocation (later we may clamp the
+  // operational length but we need to maintain a consistent object
+  // length so that the object can be traversed during GC).
+  intptr_t allocated_length_;
 
-  // Variable length data follows here.
-  BN_ULONG data_[0];
+  // Operation length of the bigint object, clamping can cause this length
+  // to be reduced. If the signed_length_ is negative then the number
+  // is negative.
+  intptr_t signed_length_;
+
+  // A sequence of Chunks (typedef in Bignum) representing bignum digits.
+  // Bignum::Chunk chunks_[Utils::Abs(signed_length_)];
+  uint8_t data_[0];
 };