export mmap_find_vma for shmat

Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 9454e66..d83a2a4 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -229,6 +229,7 @@
 extern unsigned long last_brk;
 void mmap_lock(void);
 void mmap_unlock(void);
+abi_ulong mmap_find_vma(abi_ulong, abi_ulong);
 void cpu_list_lock(void);
 void cpu_list_unlock(void);
 #if defined(USE_NPTL)