diff --git a/gfan.spec b/gfan.spec
index 090b5aa..934ca85 100644
--- a/gfan.spec
+++ b/gfan.spec
@@ -50,6 +50,8 @@ BuildRequires:  tex(english.ldf)
 %endif
 %endif
 %endif
+# Software requires the presence of __int128; possibly relevant for armv7l too
+ExcludeArch:    %ix86
 
 %description
 Gfan is a software package for computing Gröbner fans and tropical