Re: Compiling kernel with -std=gnu11

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Sun, 5 Jan 2025 16:19:50 +0100
> From: Anders Magnusson <ragge%tethuvudet.se@localhost>
> 
> Den 2025-01-05 kl. 15:48, skrev Taylor R Campbell:
> > Any objections to compiling the kernel with -std=gnu11 instead?
> What are the reasons why we cannot use -std=c11 instead in that case?

Good question!  I just tried building aarch64 and i386 GENERIC kernels
with -std=c11 and the only issue that came up was the use of the
nonstandard keywords asm and typeof.  Compiling with -std=c11
-Dasm=__asm -Dtypeof=__typeof worked fine.

I skimmed through
https://gcc.gnu.org/onlinedocs/gcc-10.5.0/gcc/C-Extensions.html
for other things whose semantics might change with -std=gnu11 vs
-std=c11, and the only case I came up with was the `\e' escape in
strings, of which we have one use:

sys/fs/udf/udf_osta.c:238:	printf("checksum: calculated=%4.4x, correct=%4.4x\en", x, 0x3299);

This looks like it might be a mistake anyway.

So maybe we can get by with -std=c11 and some judiciously placed
#define asm __asm and similar without any effort beyond that.