Export symbols in order to support shared libraries (#54)

* Add BAC_ROUTING compile definition

* Reorder cmake

* Fix OpenSSL support: support both 1.0 and 1.1t pus

* Explicitly export symbols, hidden by default

* Build shared libraries on travis using cmake

* Learn Makefile about static library

* Fix build using mingw with cmake

* Do not cleanup twice or after potential free

src/bacnet/basic/bbmd6/vmac.h

@@ -8,6 +8,7 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include "bacnet/bacnet_stack_exports.h"
 
 /* define the max MAC as big as IPv6 + port number */
 #define VMAC_MAC_MAX 18
@@ -26,22 +27,32 @@ struct vmac_data {
 extern "C" {
 #endif /* __cplusplus */
 
+    BACNET_STACK_EXPORT
     unsigned int VMAC_Count(void);
+    BACNET_STACK_EXPORT
     struct vmac_data *VMAC_Find_By_Key(uint32_t device_id);
+    BACNET_STACK_EXPORT
     bool VMAC_Find_By_Data(struct vmac_data *vmac, uint32_t *device_id);
+    BACNET_STACK_EXPORT
     bool VMAC_Add(uint32_t device_id, struct vmac_data *pVMAC);
+    BACNET_STACK_EXPORT
     bool VMAC_Delete(uint32_t device_id);
+    BACNET_STACK_EXPORT
     bool VMAC_Different(
         struct vmac_data *vmac1,
         struct vmac_data *vmac2);
+    BACNET_STACK_EXPORT
     bool VMAC_Match(
         struct vmac_data *vmac1,
         struct vmac_data *vmac2);
+    BACNET_STACK_EXPORT
     void VMAC_Cleanup(void);
+    BACNET_STACK_EXPORT
     void VMAC_Init(void);
 
 #ifdef TEST
 #include "ctest.h"
+    BACNET_STACK_EXPORT
     void testVMAC(
         Test * pTest);
 #endif