https://sourceforge.net/mailarchive/forum.php?thread_name=k2vfc2c80ae1004051048n4a2b5ab0y85ab946c2a556544%40mail.gmail.com&forum_name=libetpan-devel
--- a/src/low-level/nntp/Makefile.am
+++ b/src/low-level/nntp/Makefile.am
@@ -35,6 +35,8 @@
 AM_CPPFLAGS = -I$(top_builddir)/include \
 	-I$(top_srcdir)/src/data-types
 
+CFLAGS += -Wno-nonnull
+
 noinst_LTLIBRARIES = libnntp.la
 
 libnntp_la_SOURCES = \