diff --git a/libinstpatch.spec b/libinstpatch.spec
index 63bac30..6a9aff1 100644
--- a/libinstpatch.spec
+++ b/libinstpatch.spec
@@ -136,7 +136,7 @@ find examples -type f -name '*.py' -print -delete
 #
 # For now, the workaround is fine on Fedora (although it does not work on
 # EPEL7–EPEL9).
-%constrain_build -c 1
+%global _smp_build_ncpus 1
 
 %cmake \
     -DGTKDOC_ENABLED:BOOL=ON \