Hello, I have a fix for libidn 1.38 regarding the Win64 platform. The use of glong in stringprep_utf8_to_ucs4[1] and other locations in nfkc.c is incorrect. The glong is a define for long: use of long type is unsafe in cross-platform code that spans through unix and windows platforms compiled with MSVC. MSVC will not scale to a 64 bit sized type when targeting for x64 hence the cast from size_t to glong pointers is unsafe and does indeed break Win64 builds. My fix is just deleting the dangerous glong define and use the safer (and more meaningful) gsize/gssize_t types instead.
You can find the patch attached. It applies to libidn 1.38 source tarball.
Cheers,
Francesco
fix-use-of-long-win64.diff