Block created curlbuild.h for NetWare to avoid usage from other platforms.

lib/Makefile.netware

@@ -616,6 +616,9 @@ $(CURL_INC)/curl/curlbuild.h: Makefile.netware FORCE
 	@echo $(DL)** Do not edit this file - it is created by make!$(DL) >> $@
 	@echo $(DL)** All your changes will be lost!!$(DL) >> $@
 	@echo $(DL)*/$(DL) >> $@
+	@echo $(DL)#ifndef NETWARE$(DL) >> $@
+	@echo $(DL)#error This $(notdir $@) is created for NetWare platform!$(DL) >> $@
+	@echo $(DL)#endif$(DL) >> $@
 	@echo $(DL)#ifndef __CURL_CURLBUILD_H$(DL) >> $@
 	@echo $(DL)#define __CURL_CURLBUILD_H$(DL) >> $@
 ifeq ($(LIBARCH),LIBC)