libmerged: add harfbuzz external

Change-Id: I7be27b049c4a482be256544c295a7aee89f81f57

Library_merged.mk

@@ -54,6 +54,7 @@ $(eval $(call gb_Library_use_externals,merged,\
 	gio \
 	graphite \
 	$(if $(ENABLE_GTK),gtk) \
+	harfbuzz \
 	hunspell \
 	icui18n \
 	icule \

vcl/Library_vcl.mk

@@ -98,24 +98,14 @@ endif
 
 $(eval $(call gb_Library_use_externals,vcl,\
 	boost_headers \
+	gio \
+	harfbuzz \
 	icule \
 	icuuc \
 	icu_headers \
 	lcms2 \
 ))
 
-ifneq ($(ENABLE_GIO),)
-$(eval $(call gb_Library_use_externals,vcl,\
-	gio \
-))
-endif
-
-ifeq ($(ENABLE_HARFBUZZ),TRUE)
-$(eval $(call gb_Library_use_externals,vcl,\
-	harfbuzz \
-))
-endif
-
 $(eval $(call gb_Library_add_exception_objects,vcl,\
     vcl/source/app/brand \
     vcl/source/app/dbggui \