diff --git a/libguile/dynl.c b/libguile/dynl.c
index 2484dda..b612709 100644
--- a/libguile/dynl.c
+++ b/libguile/dynl.c
@@ -121,6 +121,17 @@ sysdep_dynl_value (const char *symb, void *handle, const char *subr)
   return fptr;
 }
 
+#ifdef __MINGW32__
+static void
+setenv (char const *name, char const *value)
+{
+  int len = strlen (value) + strlen (value) + 2;
+  char *str = malloc (len);
+  sprintf (str, "%s=%s", name, value);
+  putenv (str);
+}
+#endif /* __MINGW32__ */
+
 /* Augment environment variable VARIABLE with VALUE, assuming VARIABLE
    is a path kind of variable.  */
 static void