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

ports/win32/bacport.h

@@ -26,6 +26,8 @@
 #ifndef BACPORT_H
 #define BACPORT_H
 
+#include "bacnet/bacnet_stack_exports.h"
+
 #define WIN32_LEAN_AND_MEAN
 #define STRICT 1
 /* Windows XP minimum */
@@ -55,7 +57,7 @@ and globals in favor of more secure versions.  */
 /* add winmm.lib to our build */
 #pragma comment(lib, "winmm.lib")
 #endif
-#include <MMSystem.h>
+#include <mmsystem.h>
 
 #if !defined(_MSC_VER)
 #include <sys/time.h>

ports/win32/rs485.h

@@ -37,6 +37,7 @@
 #define RS485_H
 
 #include <stdint.h>
+#include "bacnet/bacnet_stack_exports.h"
 #include "bacnet/datalink/mstp.h"
 #include "bacport.h"
 
@@ -44,32 +45,42 @@
 extern "C" {
 #endif /* __cplusplus */
 
+    BACNET_STACK_EXPORT
     void RS485_Set_Interface(
         char *ifname);
+    BACNET_STACK_EXPORT
     const char *RS485_Interface(
         void);
 
+    BACNET_STACK_EXPORT
     void RS485_Initialize(
         void);
 
+    BACNET_STACK_EXPORT
     void RS485_Send_Frame(
         volatile struct mstp_port_struct_t *mstp_port,  /* port specific data */
         uint8_t * buffer,       /* frame to send (up to 501 bytes of data) */
         uint16_t nbytes);       /* number of bytes of data (up to 501) */
 
+    BACNET_STACK_EXPORT
     void RS485_Check_UART_Data(
         volatile struct mstp_port_struct_t *mstp_port); /* port specific data */
 
+    BACNET_STACK_EXPORT
     uint32_t RS485_Get_Baud_Rate(
         void);
+    BACNET_STACK_EXPORT
     bool RS485_Set_Baud_Rate(
         uint32_t baud);
 
+    BACNET_STACK_EXPORT
     void RS485_Print_Error(
         void);
 
+    BACNET_STACK_EXPORT
     bool RS485_Interface_Valid(
         unsigned port_number);
+    BACNET_STACK_EXPORT
     void RS485_Print_Ports(
         void);