diff --git a/t/dynoplibs/trans.t b/t/dynoplibs/trans.t
index f64e222..bc8e990 100644
--- a/t/dynoplibs/trans.t
+++ b/t/dynoplibs/trans.t
@@ -493,11 +493,11 @@ Tests various transcendental operations
     config = interp[.IGLOBALS_CONFIG_HASH]
     .local int intvalsize
     intvalsize = config['intvalsize']
-    .local int gmp
+    .local string gmp
     gmp = config['gmp']
 
     if intvalsize != 4 goto can_test
-    if gmp goto can_test
+    if gmp == 'define' goto can_test
         skip(40,'No integer overflow for 32-bit INTVALs without GMP installed')
         goto end