Visual Studio C++ Preprocessor behavior changed? - visual-studio

Question

I'm using Visual Studio C++ Preprocessor to preprocess some files which are not C or C++ files (I find it very convenient).
Recently I upgraded from Visual Studio 2010 to 2015 and found out that the preprocessor behavior slightly changed. Some text that works on VS2010 gives an error on VS2015 and vice versa.
To illustrate the difference, here are two one liner files, ok2010.c and ok2015.c, and the preprocessing command line running with VS2010 and VS2015:
ok2010.c:
#define X `0'`'
ok2015.c:
#define X `0'`'`'
Preprocessing on VS2010:
c:\>cl -E ok2010.c
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
ok2010.c
#line 1 "ok2010.c"
c:\>cl -E ok2015.c
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
ok2015.c
#line 1 "ok2015.c"
ok2015.c(1) : error C2001: newline in constant
Preprocessing on VS2015:
c:\>cl -E ok2010.c
Microsoft (R) C/C++ Optimizing Compiler Version 19.00.23506 for x86
Copyright (C) Microsoft Corporation. All rights reserved.
ok2010.c
#line 1 "ok2010.c"
ok2010.c(1): error C2001: newline in constant
c:\>cl -E ok2015.c
Microsoft (R) C/C++ Optimizing Compiler Version 19.00.23506 for x86
Copyright (C) Microsoft Corporation. All rights reserved.
ok2015.c
#line 1 "ok2015.c"
I guess that the preprocessor handles differently tick (') and backtick (`), and expects them to be balanced. When they are not balanced it reports a newline in a quoted constant expression.
VS2010 ignores backtick entirely and expects only the ticks to be balanced, so this behavior makes sense.
However, I can't make sense of VS2015 behavior since it works only when both ticks and backticks are not balanced...
Any idea?