Define CORERT for ProjectN builds

CoreRT is component of ProjectN (aka .NET Native for UWP), but our current defines do not reflect it because of CORERT is not defined in ProjectN builds. This creates confusion for folks outside the core runtime team, and conflicts with our documentation. For example, https://github.com/dotnet/corert/blob/master/Documentation/intro-to-corert.md says "CoreRT is the .NET Core runtime that is optimized for AOT scenarios, which .NET Native targets". It does not say "CoreRT is the .NET Core runtime optimized for AOT scenarios that uses RyuJIT backend" or anything like that.

- Before this change:
     PROJECTN: defined in closed source ProjectN builds
     CORERT: defined in open source CoreRT builds
     CORECLR: defined in CoreCLR builds

- After this change:
     PROJECTN: defined in closed source ProjectN builds (same)
     CORERT: defined in both open source CoreRT builds and closed source ProjectN builds (different)
     CORECLR: defined in CoreCLR builds (same)

[tfs-changeset: 1680901]

1 files changed, 3 insertions, 3 deletions

diff --git a/src/Native/Runtime/MathHelpers.cpp b/src/Native/Runtime/MathHelpers.cpp
index e299c26bb..88a26a556 100644
--- a/src/Native/Runtime/MathHelpers.cpp
+++ b/src/Native/Runtime/MathHelpers.cpp
@@ -15,8 +15,8 @@ EXTERN_C REDHAWK_API UInt64 REDHAWK_CALLCONV RhpDbl2ULng(double val)
     return((UInt64)val);
 }
 
-// CORERT Specific - on Project N the arguments to these helpers are inverted
-#ifdef CORERT
+// On ProjectN the arguments to these helpers are inverted
+#ifndef PROJECTN
 #undef min
 #undef max
 #include <cmath>
@@ -80,7 +80,7 @@ EXTERN_C REDHAWK_API float REDHAWK_CALLCONV RhpFltRound(float value)
     return roundf(value);
 }
 
-#endif // CORERT
+#endif // !PROJECTN
 
 #ifdef _ARM_
 EXTERN_C REDHAWK_API Int32 REDHAWK_CALLCONV RhpIDiv(Int32 i, Int32 j)