By default 'curl -s' (for silent) will swallow any errors that occur during the retrieval of the URL. This makes problems rather difficult to debug. The '-S' flag changes this behaviour: "When used with -s it makes curl show an error message if it fails" (from the manpage)
curl_verbose_ = $(curl_verbose_$(AM_DEFAULT_VERBOSITY))
curl_verbose_0 = @echo " CURL " $@;
$(srcdir)/effective_tld_names.dat:
- $(curl_verbose)if ! curl -s https://publicsuffix.org/list/public_suffix_list.dat > $@; then rm -f $@; exit 1; fi
+ $(curl_verbose)if ! curl -s -S https://publicsuffix.org/list/public_suffix_list.dat > $@; then rm -f $@; exit 1; fi
pubsuffix.cc: $(srcdir)/effective_tld_names.dat
$(AM_V_GEN)./mkpubsuffixcc