I am uploading another NMU to fix this.
The debdiff is attached.
diff -Nru leaktracer-2.4/debian/changelog leaktracer-2.4/debian/changelog
--- leaktracer-2.4/debian/changelog 2023-09-29 12:17:22.000000000 +0200
+++ leaktracer-2.4/debian/changelog 2023-10-09 18:11:18.000000000 +0200
@@ -1,3 +1,10 @@
+leaktracer (2.4-6.3) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * Drop CFLAGS from test run, which results in FTBFS (Closes: #1053727).
+
+ -- Bastian Germann <b...@debian.org> Mon, 09 Oct 2023 18:11:18 +0200
+
leaktracer (2.4-6.2) unstable; urgency=medium
* Non-maintainer upload.
diff -Nru leaktracer-2.4/debian/rules leaktracer-2.4/debian/rules
--- leaktracer-2.4/debian/rules 2023-09-29 12:17:22.000000000 +0200
+++ leaktracer-2.4/debian/rules 2023-10-09 18:11:03.000000000 +0200
@@ -27,7 +27,7 @@
dh_testdir
$(MAKE) CC="$(CXX)" CFLAGS="${CFLAGS}"
- [ $(NOCHECK) = 1 ] || $(MAKE) test CC="$(CXX)" CFLAGS="${CFLAGS}"
+ [ $(NOCHECK) = 1 ] || $(MAKE) test CC="$(CXX)"
touch build-stamp
