Fix sim-eng build.

Appears to have been broken by:

commit 9779b221e9
Author: Mathias Agopian <mathias@google.com>
Date:   Mon Sep 7 16:32:45 2009 -0700

    fix [2068105] implement queueBuffer/lockBuffer/dequeueBuffer properly

For some reason we don't like to have "-lpthread" globally -- it's a no-op
on device builds, but required for many host tools and all sim binaries --
so adding the use of pthread calls requires adding the library explicitly.

libs/ui/Android.mk

@@ -40,4 +40,8 @@ LOCAL_SHARED_LIBRARIES := \
 
 LOCAL_MODULE:= libui
 
+ifeq ($(TARGET_SIMULATOR),true)
+    LOCAL_LDLIBS += -lpthread
+endif
+
 include $(BUILD_SHARED_LIBRARY)