BUG #15524: Unable to run perl mkvcbuild.pl

The following bug has been logged on the website:

Bug reference: 15524
Logged by: David Demelier
Email address: demelier.david@gmail.com
PostgreSQL version: 11.1
Operating system: Windows 10
Description:

Hello,

I'm reading the PostgreSQL documentation about building on Windows. I've
opened a Visual Studio 2017 x64 native command prompt and gone into the
src\tools\msvc directory.

Then, with activestate's bin directory into %PATH%, I've ran perl
mkvcbuild.pl and the following error happened:

Generating pg_config.h...
Use of uninitialized value in multiplication (*) at
C:\Users\d8d\Downloads\postgresql-11.1\src\tools\msvc/Solution.pm line 181,
<$i> line 782.
Use of uninitialized value in division (/) at
C:\Users\d8d\Downloads\postgresql-11.1\src\tools\msvc/Solution.pm line 184,
<$i> line 782.
Illegal division by zero at
C:\Users\d8d\Downloads\postgresql-11.1\src\tools\msvc/Solution.pm line 184,
<$i> line 782.

I've also tried to run build directly but failed saying that corecrt.h.
Also, even if the pg_config.h generation is incomplete, it looks like your
custom build system detect not correctly the version number because the .sln
files targets Windows 8 platform by default.