diff --git a/heaptrack.spec b/heaptrack.spec
index 071ae96..b75e73a 100644
--- a/heaptrack.spec
+++ b/heaptrack.spec
@@ -85,9 +85,7 @@ A Qt5/KF5 based GUI for Heaptrack.
 # Disable building tests, they're not used and post-build-checks trips over it
 sed -i"" '/add_subdirectory(tests)/d' CMakeLists.txt
 
-%if "%{_lib}" == "lib64"
-_lib_suffix=64
-%endif
+_lib_suffix=$(echo %_lib | cut -b4-)
 
 %build
   %cmake_kf5 -d build -- -DLIB_SUFFIX="$_lib_suffix"