[Lazarus] How to build FPC/Lazarus from sources on Windows?

[Bo Berglund]

I am used to installing FPC/Lazarus on Linux machines from sources via
svn. I have created a script that does most of the necessary stuff for
this.

Now I want to do the same on Windows7, but I am not really sure how.
When I google I get old instructions from the Lazarus 0.9 times, so
these are not especially useful.
Just one item: make

This is a necessary item to be able to build both FPC and Lazarus, yet
on my machine the only make utility I find are these:

where make
C:\Programs\CodeGear\RAD Studio\6.0\bin\make.exe
C:\Programs\Embarcadero\RAD Studio\12.0\bin\make.exe
C:\Programs\Borland\BDS\4.0\Bin\make.exe
C:\Programs\CodeGear\RAD Studio\5.0\bin\make.exe
C:\Programs\Borland\Delphi7\Bin\make.exe

As you can see there are no less than 5 different make utilities all
coming from various installations of Delphi/RAD Studio.

Are these OK to use or do I need to get (how?) some other make
utility? Maybe a GNU version???

Is there an up-to-date page describing the exact procedure to build
FPC and Lazarus from sources retrieved via SVN on Windows?

I do have several older versions of Lazarus/fpc installed already
(1.6, 1.8, 1.8.4 32 bit) but none seems to put fpc.exe on path.
The fpc version for the 1.8.x lazarus is 3.0.4 bundeled with their
respective and 1.6 uses fpc 3.0.0.

I want to move forward with this and not rely on some binary package
if possible.

-- 
Bo Berglund
Developer in Sweden