1 files changed, 7 insertions, 0 deletions
diff --git a/hash.c b/hash.c
index 79f6542a4e..8a219aa061 100644
--- a/hash.c
+++ b/hash.c
@@ -1048,6 +1048,13 @@ ruby_setenv(name, value)
     SetEnvironmentVariable(name,value);
 #endif
 
+#elif defined __CYGWIN__
+#undef setenv
+#undef unsetenv
+    if (value)
+	setenv(name,value,1);
+    else
+	unsetenv(name);
 #else  /* WIN32 */
 
     int i=envix(name);		        /* where does it go? */