compiler warnings on 32-bit environment

[freakout42]

[  2%] Building CXX object libheif/CMakeFiles/heif.dir/bitstream.cc.o
/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/bitstream.cc: In constructor 'StreamReader_memory::StreamReader_memory(const uint8_t*, int64_t, bool)':
/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/bitstream.cc:75:32: warning: conversion from 'int64_t' {aka 'long long int'} to 'size_t' {aka 'unsigned int'} may change value [-Wconversion]
   75 |     memcpy(m_owned_data, data, m_length);
      |                                ^~~~~~~~

/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/bitstream.cc: In member function 'bool BitstreamRange::read(uint8_t*, int64_t)':
/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/bitstream.cc:269:35: warning: conversion from 'int64_t' {aka 'long long int'} to 'size_t' {aka 'unsigned int'} may change value [-Wconversion]
  269 |   bool success = istr->read(data, n);
      |                                   ^
[  4%] Building CXX object libheif/CMakeFiles/heif.dir/box.cc.o

/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/box.cc: In member function 'virtual Error Box_colr::parse(BitstreamRange&)':
/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/box.cc:1879:34: warning: conversion from 'long long unsigned int' to 'std::vector::size_type' {aka 'unsigned int'} may change value [-Wconversion]
 1879 |     std::vector rawData(profile_size);
      |                                  ^~~~~~~~~~~~

/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/box.cc: In member function 'virtual Error Box_av1C::parse(BitstreamRange&)':
/home/axel/p/rpm/BUILD/libheif-1.16.1/libheif/box.cc:3313:24: warning: conversion from 'int64_t' {aka 'long long int'} to 'std::vector::size_type' {aka 'unsigned int'} may change value [-Wconversion]
 3313 |   m_config_OBUs.resize(configOBUs_bytes);
      |                        ^~~~~~~~~~~~~~~~