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From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Cc: Siddhesh Poyarekar <siddhesh@redhat.com>
Subject: C90 header compatibility
Date: Mon, 30 Jan 2023 08:58:19 +0100
Message-ID: <871qnc1mjo.fsf@oldenburg.str.redhat.com>
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We regressed compatibility with C90 compilers because <sys/cdefs.h>
unconditionally uses variadic macros, a C99 feature, in the definition
of __glibc_fortify and __glibc_fortify_n.

This also impacts certain C++ compilers that do not have a
C99-compatible preprocessor.

Should we fix this?  I think so.

Previously, we worked around this by enclosing variable-length lists in
(=E2=80=A6), but it doesn't look like it might work here.  We probably need=
 to
move the macros into a separate file, and include that file only if
fortification is active.

Thanks,
Florian