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Date:   Wed, 14 Jul 2021 15:22:08 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Alexey Dobriyan <adobriyan@gmail.com>
Cc:     akpm@linux-foundation.org, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        arnd@arndb.de
Subject: Re: [PATCH] Decouple build from userspace headers
Message-ID: <YO7zEFNSXOY8pKCQ@infradead.org>
References: <YO3txvw87MjKfdpq@localhost.localdomain>
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> -#define signals_blocked false
> +#define signals_blocked 0

Why can't we get at the kernel definition of false here?

> new file mode 100644
> --- /dev/null
> +++ b/include/stdarg.h
> @@ -0,0 +1,9 @@
> +#ifndef _LINUX_STDARG_H
> +#define _LINUX_STDARG_H
> +typedef __builtin_va_list __gnuc_va_list;
> +typedef __builtin_va_list va_list;
> +#define va_start(v, l)	__builtin_va_start(v, l)
> +#define va_end(v)	__builtin_va_end(v)
> +#define va_arg(v, T)	__builtin_va_arg(v, T)
> +#define va_copy(d, s)	__builtin_va_copy(d, s)
> +#endif

Empty lines before and after the include guards would be nice.

What do we need the __gnuc_va_list typedef for?

Otherwise this looks great.  As a follow on maybe move the new header
to <linux/stdarg.h> to make clear to everyone that we are using our
own version.