This is binary build of William Joye's TkBLT.
How to build
./configure --prefix=/c/bin/tcl8.6.10 --with-tcl=/c/src/tcl8.6.10/win --with-tk=/c/src/tk8.6.10/win --enable-threads CC=g++ CPPFLAGS="-static" make install
./configure --prefix=/c/bin/tcl8.6.10-x64 --with-tcl=/c/src/tcl8.6.10-x64/win --with-tk=/c/src/tk8.6.10-x64/win --enable-threads CC=g++ --enable-64bit CPPFLAGS="-static" make install
I needed to delete the following files in MSYS2 in order to remove the dependency on MinGW DLLs. CPPFLAGS="-static" was not enough.
Tcl patchlevel insensitive patch
TkBLT is a stab-enabled package but it works with the exact patchlevel at which it was built. I used Tcl/Tk 8.6.8. So it can't be used in 8.6.7 or 8.6.9. I found a workaround. Note that it might be against author's intention.