diff --git a/shaderc.changes b/shaderc.changes
index 8a87157..2cd8ccd 100644
--- a/shaderc.changes
+++ b/shaderc.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Thu Nov  9 15:46:07 UTC 2023 - Dominique Leuenberger <dimstar@opensuse.org>
+
+- Fix previous change: export to CXXFLAGS instead of CPPFLAGS so
+  that it's actually picked up. Add optflags to CXXFLAGS to ensure
+  it's not lost.
+
 -------------------------------------------------------------------
 Thu Nov  2 18:07:38 UTC 2023 - Jan Engelhardt <jengelh@inai.de>
 
diff --git a/shaderc.spec b/shaderc.spec
index 3992972..bb2bdf1 100644
--- a/shaderc.spec
+++ b/shaderc.spec
@@ -70,7 +70,7 @@ chmod a+x utils/update_build_version.sh
 echo "\"%version\"" >glslc/src/build-version.inc
 
 %build
-export CPPFLAGS="-I%_includedir/External"
+export CXXFLAGS="%{optflags} -I%_includedir/External"
 %cmake -DSHADERC_SKIP_TESTS=ON
 %cmake_build