Workaround is to execute "setenv CC gcc" before "pkg install".
Unofficial 64 bit binary is available at " File list of Octave for Windows". release installers and zip archived packages can be found at /gnu/octave/windows/.
The easiest way to install GNU Octave on Microsoft Windows is using MXE builds. To manually install a new or updated package version, the package file can be downloaded from the Octave Forge website to the working directory and can be installed using:
Manual package installation is necessary with this version to update or install new packages on Windows.
However, note that version 4.2.0 has a bug that prevents it from automatically retrieving packages from the Octave Forge website for installation or updates. The instructions for Octave 4.2.0 - 4.2.2 are the same as for Octave 4.4.0. (Right-click on the shortcut, select Properties, and add -force-gui to the end of the Target field.) Later versions reverted back to the previous behavior where graphical user interface runs by default. The user needs to add -force-gui to any manual shortcuts to start Octave with the GUI. In addition to the post-install instructions above for Octave 4.4.1, in Octave 4.4.0 the shortcuts start the command line interface, not the graphical user interface, by default. After unzipping the package and creating shortcuts, the user is required to first run the fc_update.bat file to rebuild the font cache and reduce first time plotting delays, and then run 'pkg rebuild' from the Octave command line to make the pre-installed packages available to the system.
In Octave 4.4.1, the post_install.bat file was not available for the 7z/Zip archives. Note that the instructions below may contain outdated links or instructions that are no longer relevant to current versions Older MXE builds Octave-4.4.1
1.2.5.2 Manual installation instructions.1.2.5 Octave-3.6.1-mingw + octaveforge pkgs.1.2.4 Octave-3.6.2-mingw + octaveforge pkgs.1.2.3.4 Optional installation of Notepad++ as an editor (recommended).1.2.3.3 Manual installation instructions for the Octave-forge packages.1.2.3.2 Manual installation instructions.1.2.3 Octave-3.6.4-mingw + octaveforge pkgs.