[Patch] Further fix for 12658

[Paolo Carlini]

Hi,

the below tweaks the current locking code as per the latest analysis
from Pétur in the audit trail.

Regtested x86/x86_64(4-way)/ia64(4-way) and checked that apparently
the only remaining failure modes are those due to the orthogonal libc
issue (now fixed in cvs by Jakub)

If nobody objects will commit soon...

Paolo.

//////////////
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: CL_12658_con
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20040729/5cb60b85/attachment.ksh>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: patch_12658_con
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20040729/5cb60b85/attachment-0001.ksh>