parisc: work around bug in gcc 4.3 and later

A bug in tail call optimisation in gcc 4.3 and later on parisc causes
numerous tests to fail.  Disabling this optimisation gives a working
build.  See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55023



Signed-off-by: Mans Rullgard <mans@mansr.com>