Add libpac, pacserver, and ProxyHandler to build.

This allows frameworks to reference libpac, ProxyHandler and pacserver as
required to add PAC support.

bug:10182711
Change-Id: Iffac836a517518bd4b9a473e09372fbd10315539
diff --git a/target/product/base.mk b/target/product/base.mk
index 846f69e..25df921 100644
--- a/target/product/base.mk
+++ b/target/product/base.mk
@@ -57,6 +57,7 @@
     libmtp \
     libnetlink \
     libnetutils \
+    libpac \
     libreference-ril \
     libreverbwrapper \
     libril \
@@ -86,6 +87,7 @@
     ndc \
     netcfg \
     netd \
+    pacserver \
     ping \
     ping6 \
     platform.xml \