PATH, exxec-path and early-init file [Windows]

[Angelo Graziosi]

The following regards the build of EMACS MASTER on Windows with MSYS2/MINGW64, 
whose tree is installed in C:\Emacs.

Trying to not add "C:/msys64/mingw64/bin" at level of Windows PATH, I added 
this to the init.el file (from 
https://emacs.stackexchange.com/questions/27326/gui-emacs-sets-the-exec-path-only-from-windows-environment-variable-but-not-from):

(add-to-list 'exec-path "C:/msys64/mingw64/bin")
(setenv "PATH" (mapconcat #'identity exec-path path-separator))

This almost works in the sense that I lose a few graphics elements (the tool 
bar icons are grayed, those of speed bar are completely lost etc.). So I moved 
those line to an early-init.el file. Indeed the Emacs manual says:

"...early-init.el. This file is loaded before the package system and GUI is 
initialized..."

"We do not recommend that you move into early-init.el customizations that can 
be left in the normal init files. That is because the early init file is read 
before the GUI is initialized..."

But the result is the same. 

In short without a correct Windows PATH it does not find all the libraries it 
needs.

It seems that what stated by the manual is a bit confusing: if early-init.el is 
loaded before GUI initialization, why shouldn't it work?

In any case is there a way to avoid to modify Windows PATH?