[PATCH] Makefile: avoid non-standard sed expressions

[Quentin Schulz]

Hi Mark,

On 11/26/24 8:12 PM, Mark Kettenis wrote:
> The '?' that is used in the sed expression that determines MK_ARCH
> is part of the extended regular expression syntax, but the default
> behaviour of sed as specified by POSIX is to use only basic regular
> expression syntax.  Use the equivalent '\{0,1\}' instead as
> suggested by the OpenBSD re_format(7) man page.
> 
> Fixes: 04b1d84221d5 ("Makefile: fix empty MK_ARCH when using ccache")

Tested-by: Quentin Schulz <quentin.schulz at cherry.de>

Considering that it's not the first time someone breaks this by making 
it non-POSIX, can you add a comment just above with a link to the 
re_format(7) man page so people are at least more aware than they are 
right now?

Thanks!
Quentin