diff --git a/libphonenumber.changes b/libphonenumber.changes
index dff5723..092aeff 100644
--- a/libphonenumber.changes
+++ b/libphonenumber.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Tue Aug 22 22:39:31 UTC 2023 - Jan Engelhardt <jengelh@inai.de>
+
+- Force-add -DNDEBUG to CFLAGS; libphonenumber relies on it.
+
 -------------------------------------------------------------------
 Mon Jun 26 09:00:14 UTC 2023 - Fabian Vogt <fvogt@suse.com>
 
diff --git a/libphonenumber.spec b/libphonenumber.spec
index 1e76114..95652f6 100644
--- a/libphonenumber.spec
+++ b/libphonenumber.spec
@@ -78,6 +78,8 @@ that use libphonenumber.
 
 %build
 cd cpp
+export CFLAGS="%optflags -DNDEBUG"
+export CXXFLAGS="$CFLAGS"
 # Enabling the geocoder breaks quite a lot due to broken cmakelists
 # (https://github.com/google/libphonenumber/pull/2556)
 %cmake -DBUILD_STATIC_LIB=OFF -DBUILD_SHARED_LIB=ON -DBUILD_TESTING=ON -DBUILD_GEOCODER=OFF -DREGENERATE_METADATA=OFF