[m-rev.] for review: support MS VC 2015

[Sebastian Godelet]

Hi Julien,

I wonder if that has to do with:
https://blogs.msdn.microsoft.com/vcblog/2014/06/18/c-runtime-crt-features-fixes-and-breaking-changes-in-visual-studio-14-ctp1/
> The printf and scanf functions are now defined inline: In order to support the two wide string format and conversion specifier modes, the definitions of all of the printf and scanf 
> functions have been moved inline into <stdio.h>, <conio.h>, and other CRT headers. This is a breaking change for any programs that declared these functions locally without
> including the appropriate CRT headers. The “fix” is to include the appropriate CRT headers
That might cause the trouble for the AC_CHECK_FUNC macro
As a side node, the VC 2015 compiler is able to compile and recompile the latest ROTD and DEV (i.e. the autoconf check wether mmc is sufficiently recent passes).
I've also tried the ADM64 arch, with a few modifications it seems to be working fine.
I've since switched to msys2, since it is so much faster than the old msys.
For now I use the MS VC that is included in the Visual Studio 2015 enterprise version (update 1).
I can also try with the community version since I guess that is the one you used to build the 14.01 32-bit version (from the homepage)

Cheers,

Sebastian.