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);}
```
