diff --git a/test-suite/runtest.sh b/test-suite/runtest.sh
index 76f1c2a..fe6ce4b 100755
--- a/test-suite/runtest.sh
+++ b/test-suite/runtest.sh
@@ -51,7 +51,8 @@ while [ $# -gt 0 ]; do
 done
 
 if [ -n "$threads" ]; then
-  thread_args="-j$threads"
+  thread_args_ninja="-j$threads"
+  thread_args_lit="j$threads"
 fi
 
 set -xe
@@ -61,6 +62,6 @@ cd $(mktemp -d)
 cmake -G Ninja $testsuite_dir \
     -DCMAKE_C_COMPILER=$cc \
     -DCMAKE_CXX_COMPILER=$cxx \
-    -DTEST_SUITE_LIT_FLAGS="-sv$thread_args"
+    -DTEST_SUITE_LIT_FLAGS="-sv$thread_args_lit"
 
-ninja $thread_args check
+ninja $thread_args_ninja check