fix(errno): add __cplusplus header

include/kernel/errno.h

@@ -2,10 +2,18 @@
 
 #include <types/types.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern uint32_t* _get_errno(void);
 
 #define errno (*_get_errno())
 
+#ifdef __cplusplus
+}
+#endif
+
 #define ENOMEM 0
 #define ENOTFOUND 1
 #define EEXIST (1 << 1)