meta: add msvc support

since bluelib is already cross-platform, this is mostly just adding
__declspec(dllexport) to the library functions.

common/include/ivy/status.h

@@ -1,6 +1,8 @@
 #ifndef IVY_COMMON_STATUS_H_
 #define IVY_COMMON_STATUS_H_
 
+#include <ivy/misc.h>
+
 enum ivy_status {
 	IVY_OK = 0,
 	IVY_ERR_EOF = -1,
@@ -10,6 +12,6 @@ enum ivy_status {
 	IVY_ERR_NOT_SUPPORTED = -5,
 };
 
-extern const char *ivy_status_to_string(enum ivy_status status);
+IVY_API const char *ivy_status_to_string(enum ivy_status status);
 
 #endif