Refactor error types and error reporting

zion/debug/debug.h

@@ -2,6 +2,20 @@
 
 #include <stdarg.h>
 
+#include "include/zerrors.h"
+
 void dbg(const char* fmt, ...);
 void dbgln(const char* str, ...);
 void panic(const char* str, ...);
+
+#define RET_ERR(expr)        \
+  {                          \
+    z_err_t _tmp_err = expr; \
+    if (_tmp_err != Z_OK) {  \
+      return _tmp_err;       \
+    }                        \
+  }
+
+#define UNREACHABLE                                \
+  panic("Unreachable %s, %s", __FILE__, __LINE__); \
+  __builtin_unreachable();