Add extern to *_main global variable declarations in header files.

- Global variables declared in header files without
  the use of the 'extern' keword will result in multiple
  instances of the variable to be created by the compiler
  -- one for each different source file in which the
  the header file is included.  This results in wasted
  memory allocated in the BSS segments as well as
  potentially introducing bugs in the application.

Change-Id: I6ef1790b60a0bd9dd3994f8510723decf258b0cc
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>

2 files changed, 3 insertions, 1 deletions

diff --git a/src/vnet/map/map.c b/src/vnet/map/map.c
index 862f7cf5612..6d18a069459 100644
--- a/src/vnet/map/map.c
+++ b/src/vnet/map/map.c
@@ -23,6 +23,8 @@
 
 #include "map.h"
 
+map_main_t map_main;
+
 /*
  * This code supports the following MAP modes:
  *
diff --git a/src/vnet/map/map.h b/src/vnet/map/map.h
index 208a58efc42..b9b3353dd2e 100644
--- a/src/vnet/map/map.h
+++ b/src/vnet/map/map.h
@@ -329,7 +329,7 @@ typedef struct {
   u16 port;
 } map_trace_t;
 
-map_main_t map_main;
+extern map_main_t map_main;
 
 extern vlib_node_registration_t ip4_map_node;
 extern vlib_node_registration_t ip6_map_node;