REORG: vars: move the "proc" scope variables out of the global struct

The presence of this field causes a long dependency chain because almost
everyone includes global-t.h, and vars include sample_data which include
some system includes as well as HTTP parts.

There is absolutely no reason for having the process-wide variables in
the global struct, let's just move them into vars.c and vars.h. This
reduces from ~190k to ~170k the preprocessed output of version.c.
diff --git a/addons/ot/src/vars.c b/addons/ot/src/vars.c
index 0db5514..fff54ac 100644
--- a/addons/ot/src/vars.c
+++ b/addons/ot/src/vars.c
@@ -72,7 +72,7 @@
 	 * source here to get the value of the 'vars' pointer, but it is defined
 	 * as 'static inline', so unfortunately none of this is possible.
 	 */
-	flt_ot_vars_scope_dump(&(global.vars), "PROC");
+	flt_ot_vars_scope_dump(&(proc_vars), "PROC");
 	flt_ot_vars_scope_dump(&(s->sess->vars), "SESS");
 	flt_ot_vars_scope_dump(&(s->vars_txn), "TXN");
 	flt_ot_vars_scope_dump(&(s->vars_reqres), "REQ/RES");
@@ -102,7 +102,7 @@
 	struct vars *retptr = NULL;
 
 	if (strcasecmp(scope, "proc") == 0)
-		retptr = &(global.vars);
+		retptr = &(proc_vars);
 	else if (strcasecmp(scope, "sess") == 0)
 		retptr = (&(s->sess->vars));
 	else if (strcasecmp(scope, "txn") == 0)
diff --git a/include/haproxy/global-t.h b/include/haproxy/global-t.h
index 8df1349..1bdbc1b 100644
--- a/include/haproxy/global-t.h
+++ b/include/haproxy/global-t.h
@@ -25,7 +25,6 @@
 #include <haproxy/api-t.h>
 #include <haproxy/buf-t.h>
 #include <haproxy/freq_ctr-t.h>
-#include <haproxy/vars-t.h>
 
 /* modes of operation (global.mode) */
 #define	MODE_DEBUG	0x01
@@ -186,7 +185,6 @@
 	unsigned int shctx_lookups, shctx_misses;
 	unsigned int req_count; /* request counter (HTTP or TCP session) for logs and unique_id */
 	int last_checks;
-	struct vars   vars;         /* list of variables for the process scope. */
 
 	/* leave this at the end to make sure we don't share this cache line by accident */
 	ALWAYS_ALIGN(64);
diff --git a/include/haproxy/global.h b/include/haproxy/global.h
index 2ff7b5d..1c50aba 100644
--- a/include/haproxy/global.h
+++ b/include/haproxy/global.h
@@ -25,7 +25,6 @@
 #include <haproxy/api-t.h>
 #include <haproxy/global-t.h>
 #include <haproxy/mworker-t.h>
-#include <haproxy/vars-t.h>
 
 extern const char *build_features;
 extern struct global global;
diff --git a/include/haproxy/vars.h b/include/haproxy/vars.h
index aeb218a..f809c62 100644
--- a/include/haproxy/vars.h
+++ b/include/haproxy/vars.h
@@ -27,6 +27,8 @@
 #include <haproxy/stream-t.h>
 #include <haproxy/vars-t.h>
 
+extern struct vars proc_vars;
+
 void vars_init(struct vars *vars, enum vars_scope scope);
 void var_accounting_diff(struct vars *vars, struct session *sess, struct stream *strm, int size);
 unsigned int var_clear(struct var *var);
diff --git a/src/haproxy.c b/src/haproxy.c
index 76fe08c..3de53bf 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -1521,7 +1521,7 @@
 	hlua_init();
 
 	/* Initialize process vars */
-	vars_init(&global.vars, SCOPE_PROC);
+	vars_init(&proc_vars, SCOPE_PROC);
 
 	global.tune.options |= GTUNE_USE_SELECT;  /* select() is always available */
 #if defined(USE_POLL)
@@ -2553,7 +2553,7 @@
 		free(tff);
 	}
 
-	vars_prune(&global.vars, NULL, NULL);
+	vars_prune(&proc_vars, NULL, NULL);
 	pool_destroy_all();
 	deinit_pollers();
 } /* end deinit() */
diff --git a/src/vars.c b/src/vars.c
index 202a9ae..572b5f5 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -21,6 +21,9 @@
 /* This contains a pool of struct vars */
 DECLARE_STATIC_POOL(var_pool, "vars", sizeof(struct var));
 
+/* list of variables for the process scope. */
+struct vars proc_vars THREAD_ALIGNED(64);
+
 /* This array contain all the names of all the HAProxy vars.
  * This permits to identify two variables name with
  * only one pointer. It permits to not using  strdup() for
@@ -47,7 +50,7 @@
 {
 	switch (scope) {
 	case SCOPE_PROC:
-		return &global.vars;
+		return &proc_vars;
 	case SCOPE_SESS:
 		return sess ? &sess->vars : NULL;
 	case SCOPE_CHECK: {
@@ -91,7 +94,7 @@
 		_HA_ATOMIC_ADD(&sess->vars.size, size);
 		/* fall through */
 	case SCOPE_PROC:
-		_HA_ATOMIC_ADD(&global.vars.size, size);
+		_HA_ATOMIC_ADD(&proc_vars.size, size);
 		_HA_ATOMIC_ADD(&var_global_size, size);
 	}
 }
@@ -128,7 +131,7 @@
 			return 0;
 		/* fall through */
 	case SCOPE_PROC:
-		if (var_proc_limit && global.vars.size + size > var_proc_limit)
+		if (var_proc_limit && proc_vars.size + size > var_proc_limit)
 			return 0;
 		if (var_global_limit && var_global_size + size > var_global_limit)
 			return 0;
@@ -187,7 +190,7 @@
 	HA_RWLOCK_WRUNLOCK(VARS_LOCK, &vars->rwlock);
 
 	_HA_ATOMIC_SUB(&vars->size, size);
-	_HA_ATOMIC_SUB(&global.vars.size, size);
+	_HA_ATOMIC_SUB(&proc_vars.size, size);
 	_HA_ATOMIC_SUB(&var_global_size, size);
 }