libiconv

libiconv is a character set conversion library from http://ftp.gnu.org/pub/gnu/libiconv/

PHP currently uses 1.12 released 2007.11.11

libiconv development has been moved to https://savannah.gnu.org/projects/libiconv/

Because iconv.exe is GPL licensed, the author has decided to drop support for building on msvc altogether, because building on newer compilers that require separate distributions of MS runtimes might cause gpl violations (you can simply point people to the runtime installers provided by microsoft and not include them with the program...but that's another story). However, libiconv is lgpl and does not have these restrictions, the versions on php.net are compiled with Microsoft compilers with a small patch to fix compiler warnings and errors.

If someone has the time or energy the patch should probably be sent upstream to the bugs list.