diff --git a/src/foreign/foreign.c b/src/foreign/foreign.c
index bee89f4ad2..8f4a910d73 100644
--- a/src/foreign/foreign.c
+++ b/src/foreign/foreign.c
@@ -978,7 +978,11 @@ ffi_abi sym_to_abi(char *who, Scheme_Object *sym)
   if (SCHEME_FALSEP(sym) || SAME_OBJ(sym, default_sym))
     return FFI_DEFAULT_ABI;
   else if (SAME_OBJ(sym, sysv_sym)) {
+#ifdef WINDOWS_DYNAMIC_LOAD
     return FFI_SYSV;
+#else
+    scheme_signal_error("%s: ABI not implemented: %V", who, sym);
+#endif
   } else if (SAME_OBJ(sym, stdcall_sym)) {
 #ifdef WINDOWS_DYNAMIC_LOAD
     return FFI_STDCALL;
diff --git a/src/foreign/foreign.ssc b/src/foreign/foreign.ssc
index 07ac3ed0ba..45a7632c86 100755
--- a/src/foreign/foreign.ssc
+++ b/src/foreign/foreign.ssc
@@ -830,7 +830,11 @@ ffi_abi sym_to_abi(char *who, Scheme_Object *sym)
   if (SCHEME_FALSEP(sym) || SAME_OBJ(sym, default_sym))
     return FFI_DEFAULT_ABI;
   else if (SAME_OBJ(sym, sysv_sym)) {
+#ifdef WINDOWS_DYNAMIC_LOAD
     return FFI_SYSV;
+#else
+    scheme_signal_error("%s: ABI not implemented: %V", who, sym);
+#endif
   } else if (SAME_OBJ(sym, stdcall_sym)) {
 #ifdef WINDOWS_DYNAMIC_LOAD
     return FFI_STDCALL;