gmake: *** No rule to make target (install cmake on gitbash, do not have makefile)

I d like to install cmake on gitbash (Windows 10) , because I need it o run shiny-server. https://github.com/rstudio/shiny-server/wiki/Building-Shiny-Server-from-Source#what-if-a-sufficiently-recent-version-of-cmake-isnt-available

When I run ./configure , it gives me the following error

*CMake 3.15.2, Copyright 2000-2019 Kitware, Inc. and Contributors
C compiler on this system is: tcc
C++ compiler on this system is: C:\MinGW\bin\g++.exe C:\MinGW\bin\g++.exe
Makefile processor on this system is: gmake
C:\MinGW\bin\g++.exe has setenv
C:\MinGW\bin\g++.exe has unsetenv
C:\MinGW\bin\g++.exe has environ in stdlib.h
C:\MinGW\bin\g++.exe has stl wstring
C:\MinGW\bin\g++.exe has <ext/stdio_filebuf.h>
---------------------------------------------
gmake: *** No rule to make target '/c/Users/../cmake-3.15.2/Source/cmAddCustomCommandCommand.cxx', neededby 'cmAddCustomCommandCommand.o'.  Stop.
---------------------------------------------
Error when bootstrapping CMake:
Problem while running gmake*

I know that the problem originates because I do not have makefile, however gnumake-windows do not possess makefile.

Could you please tell me how I can overcome this issue, or how I can install cmake on windows , or how I can run shiny-server on windows ?

With lots of thanks