qemu fix for gcc3/4 mixed systems

[Kok, Auke]

Terry,

please apply this to your qemu module and see if it still builds OK. This will 
allow qemu to compile on gcc3-only and also gcc3/4 mixed systems

Cheers,

Auke

---
diff a/devel/qemu b/devel/qemu
--- a/devel/qemu/BUILD  2007-02-15 11:01:03.000000000 -0800
+++ b/devel/qemu/BUILD  2007-04-20 10:39:08.000000000 -0700
@@ -6,7 +6,9 @@
      OPTS+=" --target-list=i386-user,i386-softmmu,arm-user,sparc-user,ppc-user"
    fi

-  default_build  &&
+  ./configure --prefix=/usr \
+                --cc=${GCC3_PREFIX:-/opt/lunar/gcc3}/bin/gcc &&
+  default_make  &&

    # qemu-doc.html may not exist, but it will be ignored if that is the case
    gather_docs TODO qemu-doc.html