We can build succeeds with gnu17.
diff -Naur tcpxtract-1.0.1.orj/debian/rules tcpxtract-1.0.1/debian/rules
--- tcpxtract-1.0.1.orj/debian/rules 2024-04-16 22:36:44.000000000 +0800
+++ tcpxtract-1.0.1/debian/rules 2026-05-28 15:41:10.540349670 +0800
@@ -3,6 +3,7 @@
export DEB_BUILD_MAINT_OPTIONS = hardening=+all
export DEB_CFLAGS_MAINT_APPEND = -DDEFAULT_CONFIG_FILE=\"/etc/tcpxtract.conf\"
+export CFLAGS += -std=gnu17
%:
dh $@ --with autoreconf
The same problem: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1138604
