World breakage: -O2 and new libthr/libc_r code

[David Xu]

libpthread used to have the warning message when being
compiled with -02, it should be fixed.

David Xu

Daniel Eriksson wrote:

>Marcel Moolenaar's latest libthr libc_r commit seems to have broken world
>for CFLAGS containing -O2.
>
>
>===> lib/libthread_db
>cc -O2 -pipe -fno-builtin -march=athlon-xp -I. -I/usr/src/lib/libthread_db
>-Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -c /u
>cc -fpic -DPIC -O2 -pipe -fno-builtin -march=athlon-xp -I.
>-I/usr/src/lib/libthread_db -Wsystem-headers -Werror -Wall -Wno-format-y2k
>-Wno-uniniti
>cc -O2 -pipe -fno-builtin -march=athlon-xp -I. -I/usr/src/lib/libthread_db
>-Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -c /u
>cc -fpic -DPIC -O2 -pipe -fno-builtin -march=athlon-xp -I.
>-I/usr/src/lib/libthread_db -Wsystem-headers -Werror -Wall -Wno-format-y2k
>-Wno-uniniti
>In file included from libpthread.h:3,
>                 from /usr/src/lib/libthread_db/libpthread_db.c:41:
>/usr/src/lib/libpthread/arch/i386/include/pthread_md.h: In function
>`_kcb_get':
>/usr/src/lib/libpthread/arch/i386/include/pthread_md.h:162: warning:
>dereferencing type-punned pointer will break strict-aliasing rules
>In file included from libpthread.h:3,
>  
>