diff --git a/ssl/kssl.c b/ssl/kssl.c
index 327b92f33b0680bb69bc608961d15a744e16c341..a80f5b2f74dad0019f31da33d79da7885911e1a0 100644
--- a/ssl/kssl.c
+++ b/ssl/kssl.c
@@ -70,6 +70,7 @@
 
 #define _XOPEN_SOURCE /* glibc2 needs this to declare strptime() */
 #include <time.h>
+#undef _XOPEN_SOURCE /* To avoid clashes with anything else... */
 #include <string.h>
 
 #include <openssl/ssl.h>