qemu-xen-traditional/configure: define _GNU_SOURCE for NPTL defs
qemu-xen/configure: use -O2 for tests to eliminate fortify warnings (-Werror is in effect sometimes)
--- xen-4.2.0/tools/qemu-xen-traditional/configure.orig	2012-09-06 18:05:30.000000000 +0200
+++ xen-4.2.0/tools/qemu-xen-traditional/configure	2012-10-27 08:16:21.702515768 +0200
@@ -738,10 +738,10 @@
 #endif
 }
 EOF
 
-if $cc $ARCH_CFLAGS -c -o $TMPO $TMPC > /dev/null 2> /dev/null ; then
+if $cc $ARCH_CFLAGS -D_GNU_SOURCE -c -o $TMPO $TMPC > /dev/null 2> /dev/null ; then
   :
 else
    nptl="no"
 fi
 
@@ -788,7 +790,7 @@
         fi
 
         # static link with sdl ?
-        if test "$sdl" = "yes" ; then
+        if test "$static" = "yes" -a "$sdl" = "yes" ; then
             aa="no"
             `$sdl_config --static-libs 2>/dev/null | grep \\\-laa > /dev/null` && aa="yes"
             sdl_static_libs=`$sdl_config --static-libs 2>/dev/null`