diff --git a/collects/compiler/private/xform.ss b/collects/compiler/private/xform.ss
index 6cea4a3d98..84287acf65 100644
--- a/collects/compiler/private/xform.ss
+++ b/collects/compiler/private/xform.ss
@@ -808,7 +808,7 @@
                
                strlen cos sin exp pow log sqrt atan2 
                isnan isinf fpclass _fpclass _isnan __isfinited
-               floor ceil round fmod fabs __maskrune _errno
+               floor ceil round fmod fabs __maskrune _errno __errno
                isalpha isdigit isspace tolower toupper
                fread fwrite socket fcntl setsockopt connect send recv close
                __builtin_next_arg __builtin_saveregs