Fix endianness issues in unit test

src/arch.h

@@ -34,21 +34,6 @@
 #define MG_ARCH MG_ARCH_RP2040
 #endif
 
-/*
- * clang with std=-c99 uses __LITTLE_ENDIAN, by default
- * while for ex, RTOS gcc - LITTLE_ENDIAN, by default
- * it depends on __USE_BSD, but let's have everything
- */
-#if !defined(BYTE_ORDER) && defined(__BYTE_ORDER)
-#define BYTE_ORDER __BYTE_ORDER
-#ifndef LITTLE_ENDIAN
-#define LITTLE_ENDIAN __LITTLE_ENDIAN
-#endif /* LITTLE_ENDIAN */
-#ifndef BIG_ENDIAN
-#define BIG_ENDIAN __LITTLE_ENDIAN
-#endif /* BIG_ENDIAN */
-#endif /* BYTE_ORDER */
-
 #if !defined(MG_ARCH)
 #include "mongoose_custom.h"  // keep this include
 #endif
@@ -58,6 +43,9 @@
 #endif
 #endif  // !defined(MG_ARCH)
 
+// http://esr.ibiblio.org/?p=5095
+#define MG_BIG_ENDIAN (*(uint16_t *)"\0\xff" < 0x100)
+
 #include "arch_esp32.h"
 #include "arch_esp8266.h"
 #include "arch_freertos_lwip.h"