Fix for GCC 4.3

Thanks to Kuja for reporting and testing and SilverLeo to know immediately
which file needs to be included.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@991 726aef4b-f618-498e-8847-2d620e286838

String.h

@@ -13,6 +13,7 @@
 #include <set>
 #include <string>
 #include <vector>
+#include <sys/types.h>
 
 using std::map;
 using std::set;