make: use -std=c99 as default

[kaspar030]

Previously, the fallback was "gnu99", but we don't allow GNU extensions by convention.

[Kijewski]

NACK because the code is full of GNU extensions ...

[kaspar030]

NACK because the code is full of GNU extensions ...

Apart from the ones fixed by this PR, where?

[Kijewski]

E.g. git grep __extension__, git grep '({', git grep typeof'.

[kaspar030]

"full of" is a little bit exaggerated.

E.g. git grep extension, git grep '({', git grep typeof'.

The former is used in "kernel_defines.h", but guarded. Keep in mind that gcc sets "GNUC" also for "-std=c99".

The latter is used for the x86 port. That could still compile with "-std=gnu99", like this PR sets for native.

Don't you think it is desirable to not use the extensions where not needed? This PR is about setting the default...

[Kijewski]

Though I like the GNU extensions, because IMO they allow you to write more readable code in some cases, I won't get a rage fit if this PR gets adopted. And finding two core developers who like this "restriction" should not be too difficult, I guess.

[Kijewski]

NACK because the code is full of GNU extensions ...

I guess Murdock proved me wrong. I'm OK with this change. ACK.

[kaspar030]

• rebased (to see if this still builds cleanly)

[kaspar030]

@ALL Any opinions on this?

[kaspar030]

I'll leave this open for two more days and then merge if noone complains.

[LudwigKnuepfer]

@kaspar030 second thoughts?