Move pigz symlinks out of GUI makefile

* Unify the building of pigz and its symlinks under the same module.
  LOCAL_POST_INSTALL_CMD has been around since Android 4.3, use it.

Change-Id: I6a1f74216b6f5a5283fc17839b9b6f19571f3be5
diff --git a/pigz/Android.mk b/pigz/Android.mk
index 9fff2f9..89f9635 100644
--- a/pigz/Android.mk
+++ b/pigz/Android.mk
@@ -12,29 +12,10 @@
 					external/zlib
 LOCAL_SHARED_LIBRARIES += libz libc
 
+LOCAL_POST_INSTALL_CMD := \
+    $(hide) mkdir -p $(TARGET_RECOVERY_ROOT_OUT)/sbin && \
+    ln -sf pigz $(TARGET_RECOVERY_ROOT_OUT)/sbin/gunzip && \
+    ln -sf pigz $(TARGET_RECOVERY_ROOT_OUT)/sbin/gzip && \
+    ln -sf pigz $(TARGET_RECOVERY_ROOT_OUT)/sbin/unpigz
+
 include $(BUILD_EXECUTABLE)
-
-PIGZ_TOOLS := unpigz
-SYMLINKS := $(addprefix $(TARGET_RECOVERY_ROOT_OUT)/sbin/,$(PIGZ_TOOLS))
-$(SYMLINKS): PIGZ_BINARY := $(LOCAL_MODULE)
-$(SYMLINKS): $(LOCAL_INSTALLED_MODULE)
-	@echo "Symlink: $@ -> $(PIGZ_BINARY)"
-	@mkdir -p $(dir $@)
-	@rm -rf $@
-	$(hide) ln -sf $(PIGZ_BINARY) $@
-
-ifneq (,$(filter $(PLATFORM_SDK_VERSION),16 17 18))
-ALL_DEFAULT_INSTALLED_MODULES += $(SYMLINKS)
-
-# We need this so that the installed files could be picked up based on the
-# local module name
-ALL_MODULES.$(LOCAL_MODULE).INSTALLED := \
-	$(ALL_MODULES.$(LOCAL_MODULE).INSTALLED) $(SYMLINKS)
-endif
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := unpigz_symlink
-LOCAL_MODULE_TAGS := optional
-LOCAL_ADDITIONAL_DEPENDENCIES := $(SYMLINKS)
-include $(BUILD_PHONY_PACKAGE)
-SYMLINKS :=