GCS_MAVLink: use can_printf_severity() for AP_Periph

libraries/GCS_MAVLink/GCS.h

@@ -1346,9 +1346,9 @@ GCS &gcs();
 #define AP_HAVE_GCS_SEND_TEXT 1
 #else
 extern "C" {
-void can_printf(const char *fmt, ...);
+    void can_printf_severity(uint8_t severity, const char *fmt, ...);
 }
-#define GCS_SEND_TEXT(severity, format, args...) (void)severity; can_printf(format, ##args)
+#define GCS_SEND_TEXT(severity, format, args...) can_printf_severity(severity, format, ##args)
 #define AP_HAVE_GCS_SEND_TEXT 1
 #endif
 
@@ -1358,12 +1358,31 @@ void can_printf(const char *fmt, ...);
 
 // map send text to can_printf() on larger AP_Periph boards
 extern "C" {
-void can_printf(const char *fmt, ...);
+    void can_printf_severity(uint8_t severity, const char *fmt, ...);
 }
-#define GCS_SEND_TEXT(severity, format, args...) can_printf(format, ##args)
+#define GCS_SEND_TEXT(severity, format, args...) can_printf_severity(severity, format, ##args)
 #define GCS_SEND_MESSAGE(msg)
 #define AP_HAVE_GCS_SEND_TEXT 1
 
+/*
+  we need a severity enum for the can_printf_severity function with no GCS present
+ */
+#ifndef HAVE_ENUM_MAV_SEVERITY
+enum MAV_SEVERITY
+{
+    MAV_SEVERITY_EMERGENCY=0,
+    MAV_SEVERITY_ALERT=1,
+    MAV_SEVERITY_CRITICAL=2,
+    MAV_SEVERITY_ERROR=3,
+    MAV_SEVERITY_WARNING=4,
+    MAV_SEVERITY_NOTICE=5,
+    MAV_SEVERITY_INFO=6,
+    MAV_SEVERITY_DEBUG=7,
+    MAV_SEVERITY_ENUM_END=8,
+};
+#define HAVE_ENUM_MAV_SEVERITY
+#endif
+
 #else // HAL_GCS_ENABLED
 // empty send text when we have no GCS
 #define GCS_SEND_TEXT(severity, format, args...)