c3-lang/libffi

diff --git a/testsuite/libffi.call/ffitest.h b/testsuite/libffi.call/ffitest.h
index 1919375..752fe55 100644
--- a/testsuite/libffi.call/ffitest.h
+++ b/testsuite/libffi.call/ffitest.h
@@ -15,7 +15,7 @@
 
 #define MAX_ARGS 256
 
-#define CHECK(x) !(x) ? (abort(), 1) : 0
+#define CHECK(x) (!(x) ? (abort(), 1) : 0)
 
 /* Define macros so that compilers other than gcc can run the tests.  */
 #undef __UNUSED__