add curl to RepositoryExternal.mk

Repository.mk

@@ -259,7 +259,6 @@ $(eval $(call gb_Helper_register_libraries,PLAINLIBS_OOO, \
 	avmediagst \
 	avmediawin \
 	collator_data \
-	curl \
 	deployment \
 	deploymentgui \
 	dict_ja \

RepositoryExternal.mk

@@ -804,7 +804,35 @@ endef
 
 endif # !SYSTEM_LIBPNG
 
-# MacOSX-only frameworks
+
+ifeq ($(SYSTEM_CURL),YES)
+
+define gb_LinkTarget__use_curl
+$(call gb_LinkTarget_set_include,$(1),\
+	$$(INCLUDE) \
+	$(CURL_CFLAGS) \
+)
+$(call gb_LinkTarget_add_libs,$(1),$(CURL_LIBS))
+
+endef
+
+else # !SYSTEM_CURL
+
+$(eval $(call gb_Helper_register_libraries,PLAINLIBS_OOO, \
+	curl \
+))
+
+define gb_LinkTarget__use_curl
+$(call gb_LinkTarget_add_linked_libs,$(1),\
+	curl \
+)
+
+endef
+
+endif # SYSTEM_CURL
+
+
+# MacOSX-only frameworks ############################################
 # (in alphabetical order)
 
 define gb_LinkTarget__use_carbon

extensions/CppunitTest_extensions_test_update.mk

@@ -40,13 +40,14 @@ $(eval $(call gb_CppunitTest_add_exception_objects,extensions_test_update, \
 $(eval $(call gb_CppunitTest_add_linked_libs,extensions_test_update, \
 	cppu \
 	cppuhelper \
-	curl \
 	sal \
 	test \
 	unotest \
 	$(gb_STDLIBS) \
 ))
 
+$(eval $(call gb_CppunitTest_use_external,extensions_test_update,curl))
+
 $(eval $(call gb_CppunitTest_set_include,extensions_test_update,\
 	$$(INCLUDE) \
 	-I$(realpath $(SRCDIR)/extensions/inc) \