Revert "serialization #defines not visible to VS2013; add manually"

This reverts commit fa806957.

serialization/src/dtoa.cpp

@@ -293,7 +293,7 @@ extern "C" {
 #endif
 
 #if defined(IEEE_8087) + defined(IEEE_MC68k) + defined(VAX) + defined(IBM) != 1
-#error Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
+Exactly one of IEEE_8087, IEEE_MC68k, VAX, or IBM should be defined.
 #endif
 
 typedef union { double d; ULong L[2]; } U;