Date: Thu, 29 Sep 2011 05:58:18 +0100 From: "Klaus T. Aehlig" <aehlig@linta.de> To: ports@freebsd.org Cc: ehaupt@FreeBSD.org Subject: clang and configure checking for equivalent simple type Message-ID: <20110929045818.GA3463@curry.linta.de>
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Hallo,
while trying to find out why I couldn't build net/socat with clang
I found something that might be a general issue, and I wonder what
appropriate actions would be.
Trying 'cd /usr/ports/net/socat && make CC=clang' failed for me and
it turned out that the reason was that the configure script could
not find out the 'equivalent simple type of off_t'. Looking at the
configure script, one notes that it tries code snippets like
#include <sys/types.h>
#include <unistd.h>
int
main ()
{
off_t u; long v; &u==&v;
;
return 0;
}
and check for compile errors. However, the above program is rejected
by clang, as the value &u==&v is unused, which, of course, has nothing
to do with the intended check whether off_t * and long * are compatible
pointer.
Adding
CFLAGS+= -Wno-unused
solves this problem.
However, I assume that these kind of tests are quite widespread in configure
scripts, so I wonder what to do about this. Possible options include
- adding 'CFLAGS+= -Wno-unused' just for this port
- do nothing, but recommend users to have -Wno-unused in CFLAGS when using clang
(maybe somewhere in the handbook)
- check with portmgr@ if adding -Wno-unused to the default CFLAGS (for clang?)
is an option
- something completely different??
(like: add an appropriate entry to my /etc/make.conf and don't care)
Any suggestions?
Best,
Klaus
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