Bug#750836: machine/atomic.h broken, missing __compiler_membar macro

[Emilio Pozuelo Monfort <pochu@debian.org>]

On 07/06/14 12:59, Romain Francoise wrote:
> Package: kfreebsd-kernel-headers
> Version: 10.0~5
> Severity: serious
> 
> libpcap is broken on kfreebsd since kfreebsd-kernel-headers was updated
> to the FreeBSD 10 headers, which apparently include this change:
> 
>  http://svnweb.freebsd.org/base?view=revision&revision=241374
> 
> The sys/cdefs.h file shipped in libc0.1-dev doesn't include the
> __compiler_membar macro, so anything that uses the atomic functions will
> get a spurious undefined reference. Here's a quick test program:
> 
> | #include <sys/types.h>
> | #include <sys/cdefs.h>
> | #include <machine/atomic.h>
> |
> | int main(int argc, char **argv)
> | {
> | 	unsigned int p, v = 0;
> | 	atomic_store_rel_int(&p, v);
> | 	return 0;
> | }
> 
> this gives:
> 
> | rfrancoise@falla ~ % gcc -Wall -o test test.c
> | /tmp/cczzxYAr.o: In function `atomic_store_rel_int':
> | test.c:(.text+0x15): undefined reference to `__compiler_membar'
> | collect2: error: ld returned 1 exit status
> | rfrancoise@falla ~ %
> 
> Thanks,

This is the last blocker for the libgnutls-deb0-28 transition. It'd be great if
someone could take a look.

Thanks,
Emilio