fixed compiler warnings issued by:

gcc 4.3
	curl.h gcc type-checking
	glibc with enabled FORTIFY_SOURCE checking

src/charon/plugins/sql/sql_attribute.c

@@ -17,6 +17,8 @@
 
 #include "sql_attribute.h"
 
+#include <time.h>
+
 #include <daemon.h>
 
 typedef struct private_sql_attribute_t private_sql_attribute_t;