external/libvncserver: use library references where possible.

By referencing libraries rather than include paths directly, a build
becomes resilient when those libraries are moved around. In this case,
external/openssl is planned to do that soon, so this change will prevent
libvncserver from breaking when that happens.

Change-Id: I2161f661de52b49eb20f27eef87bb27316b941bd

Android.mk

diff --git a/Android.mk b/Android.mk
index 6b19ad9..3f4197f 100644
--- a/Android.mk
+++ b/Android.mk
@@ -7,13 +7,8 @@
                     $(LOCAL_PATH)/libvncserver \
                     $(LOCAL_PATH) \
                     $(LOCAL_PATH)/common \
-                    external/zlib \
-                    external/libpng \
-                    external/openssl/include \
                     external/jpeg
 
-common_static_libraries := libz libpng libjpeg_static libssl_static
-
 LOCAL_SRC_FILES := libvncserver/auth.c \
                    libvncserver/cargs.c \
                    libvncserver/corre.c \
@@ -46,9 +41,9 @@
                    common/sha1.c \
                    common/turbojpeg.c \
                    common/vncauth.c \
-                   test/bmp.c 
+                   test/bmp.c
 
-LOCAL_STATIC_LIBRARIES :=
+LOCAL_STATIC_LIBRARIES := libz libpng libjpeg_static libssl_static
 LOCAL_CFLAGS := -D__ANDROID__ -DHAVE_LIBSSL -DWITH_WEBSOCKETS
 
 #LOCAL_SDK_VERSION := 14