Do not define ENABLE_ROOTWRAP on OS/2

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
(cherry picked from commit 7126cec9)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

src/network/rootbind.c

@@ -24,7 +24,7 @@
 
 #define _XPG4_2 /* ancilliary data on Solaris */
 
-#if !defined (WIN32)
+#if !defined (WIN32) && !defined (__OS2__)
 # define ENABLE_ROOTWRAP 1
 #endif