Support for LOCAL_HAL_STATIC_LIBRARIES

Now you can have a board config variable BOARD_HAL_STATIC_LIBRARIES,
which is a list of board-specific HAL static library names with pattern
"lib<library_name>.<board_specific_suffix>". LOCAL_HAL_STATIC_LIBRARIES
is a list of "lib<library_name>" and any matched
BOARD_HAL_STATIC_LIBRARIES will be added to the LOCAL_STATIC_LIBRARIES;
if no match is found, lib<library_name>.default will be used.

Bug: 10262105
Change-Id: Ic89d8d417d1dd65a227e4187a157fd3b77c4af34
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index ca1fea7..8940c3a 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -139,6 +139,7 @@
 LOCAL_PREBUILT_MODULE_FILE:=
 LOCAL_POST_INSTALL_CMD:=
 LOCAL_DIST_BUNDLED_BINARIES:=
+LOCAL_HAL_STATIC_LIBRARIES:=
 
 # Trim MAKEFILE_LIST so that $(call my-dir) doesn't need to
 # iterate over thousands of entries every time.