Problems in the makefile.vc and test files prevent the thread package from being successfully built on Win32 using MSVC6 or MSVC8.
(1) The link flag -nodefaultlib:msvcrt has been added in the case of non-static builds (which must link against MSVCRT). This was probably added in error because Thread failed to link against a Tcl DLL which was compiled with different library flags (-MT instead of -MD). This flag must be removed.
(2) tests/all.tcl doesn't correctly load the Thread DLL (specified via -loadfile by the makefile.vc), so tests can't run at all.
(3) tests/thread.test attempts to resolve $::tcl_PatchLevel on non-unix platforms (note capatalisation error: should be $::tcl_patchLevel).
The attached patch fixes all these errors and bumps the package version to 2.6.6 (in configure.in and pkg.vc). The maintainer will need to reconfigure.