Add include of sys/select.h for FD_ISSET definition

--- pkcs11/rpc-layer/gkm-rpc-daemon-standalone.c	2015-06-01 08:19:06.507624249 +0200
+++ pkcs11/rpc-layer/gkm-rpc-daemon-standalone.c	2015-06-01 08:19:45.070624135 +0200
@@ -31,6 +31,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/select.h>
 
 #include <dlfcn.h>
 #include <pthread.h>