Allow a clean shutdown on window system failure

[lrusak]

I have been investigating why we segfault when windowing cannot be initialized.

This allows a clean shutdown if false is return somewhere in InitWinSystem()

If this isn't desired it would still be nice to add the nullptr checks

[FernetMenta]

nice. I misinterpreted the intent of this code in the morning. This looks good

[lrusak]

@FernetMenta thank you. Please note that the GLES renderer changes were do to some odd behaviour in the way std::unique_ptr<CGLESShader*[]> m_pShader; was working with nullptr checks.

It seems that

if (m_pShader[SM_DEFAULT])

was passing the nullptr check for some reason and this would cause a segfault in the Free()

I'm not sure why this was or if someone can explain this behaviour to me. Regardless I think the std::array<std::unique_ptr<CGLESShader>, SM_MAX> m_pShader; format looks better anyways.

If you want me to do this to GL just say so unless you want to do it 😉

[FernetMenta]

@lrusak I noticed this problem too as I did: #14612
If ReleaseShaders was called before InitShaders it crashed. I came to this solution with an init member: 1d06fd4
Your solution seems to be more elegant. Please go ahead if you have time.

[lrusak]

@FernetMenta care to give this a test before merging?

[MartijnKaijser]

jenkins build this please

[FernetMenta]

I tested the GL commit here: works