[MEDIUM] move global tuning options to the global structure

The global tuning options right now only concern the polling mechanisms,
and they are not in the global struct itself. It's not very practical to
add other options so let's move them to the global struct and remove
types/polling.h which was not used for anything else.
diff --git a/src/cfgparse.c b/src/cfgparse.c
index af72b15..6defe9e 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -32,7 +32,6 @@
 
 #include <types/capture.h>
 #include <types/global.h>
-#include <types/polling.h>
 
 #include <proto/acl.h>
 #include <proto/backend.h>
@@ -292,16 +291,16 @@
 		global.mode |= MODE_DEBUG;
 	}
 	else if (!strcmp(args[0], "noepoll")) {
-		cfg_polling_mechanism &= ~POLL_USE_EPOLL;
+		global.tune.options &= ~GTUNE_USE_EPOLL;
 	}
 	else if (!strcmp(args[0], "nosepoll")) {
-		cfg_polling_mechanism &= ~POLL_USE_SEPOLL;
+		global.tune.options &= ~GTUNE_USE_SEPOLL;
 	}
 	else if (!strcmp(args[0], "nokqueue")) {
-		cfg_polling_mechanism &= ~POLL_USE_KQUEUE;
+		global.tune.options &= ~GTUNE_USE_KQUEUE;
 	}
 	else if (!strcmp(args[0], "nopoll")) {
-		cfg_polling_mechanism &= ~POLL_USE_POLL;
+		global.tune.options &= ~GTUNE_USE_POLL;
 	}
 	else if (!strcmp(args[0], "quiet")) {
 		global.mode |= MODE_QUIET;