The initial use was incorrect - it assumed that on big endian, the bytes
b0,b1,b2,b3 need to be swapped so value b[0] would be what was b[3]
on little-endian which is not true (writting bytes)
This mistake has then spread across UltraGrid.
WORDS_BIGENDIAN is defiend by config.h
Use __BYTE_ORDER__ defined by GNU compilers (POSIX 2024 further defines
endian.h header but not yet in macOS /15/),
suppress a warning in AJA headers (as it already is in vcap/aja):
```
/usr/local/include/libajantv2/ajantv2/includes/ntv2formatdescriptor.h:230:113: error: cast from type ‘const void*’ to type ‘UByte*’ {aka ‘unsigned char*’} casts away qualifiers [-Werror=cast-qual]
230 | inline UByte * GetTopVisibleRowAddress (UByte * pInStartAddress) const {return (UByte *) GetRowAddress (pInStartAddress, firstActiveLine);}
```
