[BUILD] make ebtree headers multiple-include compatible

ebtree did not support being included multiple times.

doc/internals/ebtree

@@ -12,3 +12,5 @@ Also, some optimizations are not redefined if already known: REGPRM*
 and likely/unlikely which are used in ebtree are also used and defined
 in haproxy. Thus, we just conditionally define them.
 
+Last, all eb*tree*.h have been adapted to support being included multiple
+times, using #ifndef/#define/#endif.

include/common/eb32tree.h

@@ -17,6 +17,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _COMMON_EB32TREE_H
+#define _COMMON_EB32TREE_H
+
 #include "ebtree.h"
 
 
@@ -511,3 +514,5 @@ __eb32i_insert(struct eb_root *root, struct eb32_node *new) {
 
 	return new;
 }
+
+#endif /* _COMMON_EB32TREE_H */

include/common/eb64tree.h

@@ -17,6 +17,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _COMMON_EB64TREE_H
+#define _COMMON_EB64TREE_H
+
 #include "ebtree.h"
 
 
@@ -532,3 +535,4 @@ __eb64i_insert(struct eb_root *root, struct eb64_node *new) {
 	return new;
 }
 
+#endif /* _COMMON_EB64TREE_H */

include/common/ebpttree.h

@@ -17,6 +17,9 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _COMMON_EBPTTREE_H
+#define _COMMON_EBPTTREE_H
+
 #include "ebtree.h"
 
 
@@ -315,3 +318,4 @@ __ebpt_insert(struct eb_root *root, struct ebpt_node *new) {
 	return new;
 }
 
+#endif /* _COMMON_EBPTTREE_H */

include/common/ebtree.h

@@ -246,6 +246,8 @@
 
  */
 
+#ifndef _COMMON_EBTREE_H
+#define _COMMON_EBTREE_H
 
 #include <stdlib.h>
 
@@ -716,6 +718,7 @@ static inline void __eb_delete(struct eb_node *node)
 void eb_delete(struct eb_node *node);
 REGPRM1 struct eb_node *eb_insert_dup(struct eb_node *sub, struct eb_node *new);
 
+#endif /* _COMMON_EBTREE_H */
 
 /*
  * Local variables: