Add -DNDEBUG to CFLAGS and CXXFLAGS in CMake build style

CMake adds -DNDEBUG with build types Release, MinSizeRel and RelWithDebInfo.
NDEBUG disables assert(), which can improve performance.

common/build-style/cmake.sh

@@ -63,8 +63,8 @@ _EOF
 	cmake_args+=" -DCMAKE_INSTALL_SBINDIR=bin"
 
 	export CMAKE_GENERATOR="${CMAKE_GENERATOR:-Ninja}"
-	# Override flags: https://gitlab.kitware.com/cmake/cmake/issues/19590
-	CFLAGS="${CFLAGS/ -pipe / }" CXXFLAGS="${CXXFLAGS/ -pipe / }" \
+	# Remove -pipe: https://gitlab.kitware.com/cmake/cmake/issues/19590
+	CFLAGS="-DNDEBUG ${CFLAGS/ -pipe / }" CXXFLAGS="-DNDEBUG ${CXXFLAGS/ -pipe / }" \
 		cmake ${cmake_args} ${configure_args} ${wrksrc}/${build_wrksrc}
 
 	# Replace -isystem with -I