diff --git a/polymake.spec b/polymake.spec
index 29028cc..d126263 100644
--- a/polymake.spec
+++ b/polymake.spec
@@ -221,7 +221,7 @@ export LC_ALL=C.UTF-8
 export CFLAGS="%{optflags} -I%{_includedir}/eigen3 -I%{_includedir}/gfanlib -I%{_includedir}/nauty -Wno-unused-local-typedefs"
 export CXXFLAGS="$CFLAGS"
 export LDFLAGS="$RPM_LD_FLAGS -lnormaliz -ldl"
-%if 0%{__isa_bits} == 32
+%if 0%{?__isa_bits} == 32
 LDFLAGS="-Wl,--no-keep-memory -Wl,--reduce-memory-overheads $LDFLAGS"
 %endif
 export Arch=%{_arch}