meson: enable pie

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -8518,6 +8518,7 @@ NINJA=$PWD/ninjatool $meson setup \
         -Ddebug=$(if test "$debug_info" = yes; then echo true; else echo false; fi) \
         -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
         -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
+        -Db_pie=$(if test "$pie" = yes; then echo true; else echo false; fi) \
         $cross_arg \
         "$PWD" "$source_path"