Add parentheses on public macros where appropriate

[bernd-edlinger]

Code-health, although today is not Tuesday :)
Fixes #3063.

[bernd-edlinger]

I don't know how much of this PR can be cherry-picked for 1.1.0 and 1.0.2
but I can create extra PRs if that is considered useful for back-porting.

[richsalz]

please do that.

[dot-asm]

Hmm... I for one would vote against taking it to released branches.

[richsalz]

okay, why?

[dot-asm]

Because these are not bugs.

[kroeckx]

I have to agree that this should go to the stable branches.

[levitte]

What would the motivation be to take this to the stable branches? @dot-asm is right, these changes aren't bug fixes per se, and they don't make future backports easier (unless we're touching these specific macros, but that happens very seldom), so yeah, I also have a hard time motivating a backport...

[richsalz]

They seem to me to fix latent bugs, such as if you do p + 1 to the BIO set-host macro.
Yes, not all of them are.

[dot-asm]

They seem to me to fix latent bugs,

Not quite, they rather prevent bugs. While definition of branch in maintenance mode is [actual] bug fixing. Well, we all know that we are quite liberal about this in 1.1.0 context, and this might be viewed as kind of a grey area, but public headers are are not as grey as rest of the code. Yes, there is contradiction here, public headers need it most, but their modification is not to be taken lightly.

[bernd-edlinger]

Ping?

[mattcaswell]

Approved for master only

[mattcaswell]

Pushed. Thanks.