stringop-overflow warning compiling with MingGW GCC 14.1.0

[rjollos]

Compiler warning with MinGW GCC 14.1.0 compiling with -O3. Not seen compiling with -O0.

Not seen for other compilers:

• macOS

 clang -v
Apple clang version 16.0.0 (clang-1600.0.26.6)
Target: arm64-apple-darwin24.3.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

• Ubuntu 24.0.4 GCC 14.2.0

11:09:11  In member function 'void picosha2::hash256_one_by_one::finish()',
11:09:11      inlined from 'void picosha2::impl::hash256_impl(RaIter, RaIter, OutIter, OutIter, int, std::random_access_iterator_tag) [with RaIter = __gnu_cxx::__normal_iterator<const char*, std::__cxx11::basic_string<char> >; OutIter = unsigned char*]' at ../../../dev-deps/picosha2/includes/picosha2.h:294:18,
11:09:11      inlined from 'void picosha2::hash256(InIter, InIter, OutIter, OutIter, int) [with InIter = __gnu_cxx::__normal_iterator<const char*, std::__cxx11::basic_string<char> >; OutIter = unsigned char*]' at ../../../dev-deps/picosha2/includes/picosha2.h:323:33,
11:09:11      inlined from 'void picosha2::hash256_hex_string(InIter, InIter, std::string&) [with InIter = __gnu_cxx::__normal_iterator<const char*, std::__cxx11::basic_string<char> >]' at ../../../dev-deps/picosha2/includes/picosha2.h:346:12:
11:09:11  ../../../dev-deps/picosha2/includes/picosha2.h:210:23: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
11:09:11    210 |         temp[remains] = 0x80;
11:09:11        |         ~~~~~~~~~~~~~~^~~~~~
11:09:11  ../../../dev-deps/picosha2/includes/picosha2.h: In function 'void picosha2::hash256_hex_string(InIter, InIter, std::string&) [with InIter = __gnu_cxx::__normal_iterator<const char*, std::__cxx11::basic_string<char> >]':
11:09:11  ../../../dev-deps/picosha2/includes/picosha2.h:206:16: note: at offset 64 into destination object 'temp' of size 64
11:09:11    206 |         byte_t temp[64];
11:09:11        |                ^~~~