VM: Make more globals constant where easily possible.

runtime/vm/globals.h

Index: runtime/vm/globals.h
diff --git a/runtime/vm/globals.h b/runtime/vm/globals.h
index 77e486a17fdb55c765d3ae6c0affc128ef87dc70..f5eef18dcb9b89ca7d997165126c3a8c854668b0 100644
--- a/runtime/vm/globals.h
+++ b/runtime/vm/globals.h
@@ -27,8 +27,8 @@ const intptr_t kSmiBits = kBitsPerWord - 2;
 const intptr_t kSmiMax = (static_cast<intptr_t>(1) << kSmiBits) - 1;
 const intptr_t kSmiMin =  -(static_cast<intptr_t>(1) << kSmiBits);
 
-const double kPosInfinity = bit_cast<double>(DART_UINT64_C(0x7ff0000000000000));
-const double kNegInfinity = bit_cast<double>(DART_UINT64_C(0xfff0000000000000));
+#define kPosInfinity bit_cast<double>(DART_UINT64_C(0x7ff0000000000000))
+#define kNegInfinity bit_cast<double>(DART_UINT64_C(0xfff0000000000000))

[Florian Schneider, 2015/11/19 16:17:00]

This was the only way I could make gcc/clang not create global variables for
these.

So far I found two alternatives:
1. Use C macros HUGE_VAL or INFINITY - these were replaced in a previous CL
(https://codereview.chromium.org//609593002).

2. Use C++11 std::numeric_limits<double>::infinity(), which is a true
compile-time constant.

[rmacnak, 2015/11/20 01:03:56]

IIRC, we hit an environment where INFINITY was either undefined or the wrong
value.

 
 // The expression ARRAY_SIZE(array) is a compile-time constant of type
 // size_t which represents the number of elements of the given