diff --git a/lib/modules/Process.pmod b/lib/modules/Process.pmod
index 8a6413b42c230eb33513020fc7e189365518e7cc..a4846e9ed8bf7e204aa65e7bfc94240c58923277 100644
--- a/lib/modules/Process.pmod
+++ b/lib/modules/Process.pmod
@@ -4,6 +4,10 @@ import Stdio;
 
 // static private inherit File : file;
 
+#if !constant(strerror)
+#define strerror(X) ("errno="+X)
+#endif
+
 varargs int exec(string file,string ... foo)
 {
   if (sizeof(file)) {