DOC: windows guide should include step to set path with mingw tools

[edmwagner]

in https://github.com/faiface/pixel/wiki/Building-Pixel-on-Windows#gcc-toolchain the proper compilers are installed but use should also add them to the path with:

export PATH=/mingw64/bin:/mingw32/bin:$PATH

Otherwise they get confusing and hard to investigate build issues in c world like

• ...errror: implicit declaration of fumction ...
• ...ld: cannot find -lmingwex
• ...ld: cannot find -lming32

I found mention of adding these to the path during investigation but it added them to WINDOWS PATH which is not inherited by the MINGW* environment by default. it was also posted as suggestions so took a while to try it.

The export above should be included and also appended to ~/.bashrc

echo 'export PATH=/mingw64/bin:/mingw32/bin:$PATH' >> ~/.bashrc

Once I did this builds were working as expected and suggested in the current docs.

[faiface]

Hi, this is a good suggestion! I'm quite busy, though. Would you be so kind and make an improved version of the wiki article in a GitHub Gist, so that I can just copy and paste it in? (The reason for this obscure way of contributing is that only I can access the wiki.) Thanks a lot.