winpthreads is enabled with --with-libraries only on i686 and not x86_64. passing --with-libraries=all should be all we need to have the library available.
Enabling it makes sense. I don't understand why explicit =all is needed though. =all/=yes (default) should be equivalent: Top-level configure.ac --with-libraries=all should already be a default with USE=libraries. only 'pseh' is conditional on the i686 target: """ AC_MSG_CHECKING([whether to build the optional libraries]) AC_ARG_WITH([libraries], [AS_HELP_STRING([--with-libraries=ARG], [Build the extra mingw-w64 libs, where ARG is comma separated list of libmangle, pseh, winpthreads, or all])], [], [with_libraries=no]) libraries="winpthreads mangle" AS_CASE([$host_cpu], [i?86], [ libraries="$libraries pseh" ]) for l in $libraries; do res=`echo "$with_libraries" | grep $l > /dev/null && echo yes || echo no` AS_CASE([$with_libraries], [all|yes],[res=yes]) AS_VAR_COPY([with_libraries_$l], [res]) done """
Now I'm confused. cross-x86_64-w64-mingw32/mingw64-runtime[libraries] does install winpthread for me: $ qlist cross-x86_64-w64-mingw32/mingw64-runtime | fgrep winpthread /usr/x86_64-w64-mingw32/usr/lib/libwinpthread.dll.a /usr/x86_64-w64-mingw32/usr/lib/libwinpthread.la /usr/x86_64-w64-mingw32/usr/lib/libwinpthread.a /usr/x86_64-w64-mingw32/usr/bin/libwinpthread-1.dll Please attach emerge --info and build.log on a system where it does not.