fftw: Add version 3.3.5

[tresf]

Adds fftw library and pkg-config files.

• Since fftw3.pc, fftw3l.pc and fftw3f.pc files were not included in the Windows distribution, I pulled the template file from upstream and configure it by hand.
• The standard /lib, /bin structure is created at install time since this library is shipped as a flat directory for windows.
  • Why? Well, pkg-config expects the prefix to be ... prefix for that package is assumed to be the grandparent of the directory where the file was found... , so the structure has been mimicked accordingly.
• As a flat directory, bin/fftw-wisdom.exe expects lib/libfftw3-3.dll side-by-side, so bin/ is a symlink to lib/ to accommodate.

This PR shouldn't be merged it is first unit tested against a basic program.

[r15ch13]

vcpkg has fftw3 available: https://github.com/Microsoft/vcpkg/blob/master/ports/fftw3/portfile.cmake

[tresf]

@r15ch13 yeah, vcpkg is slowly becoming the "de facto" standard for automated Windows builds that rely on historically POSIX libraries like fftw. There are some things to be learned from their approach, such as how they fix the lib and bin aliases using vcpkg_fixup_cmake_targets macro.

Unfortunately, this only helps those building fftw from source. The purpose of this PR was to provide a precompiled fftw library and all of the tools needed for pkg-config and cmake to pick it up while searching for dependencies.

Sorry the PR has been open for so long. If you wish, you may close it out. I've postponed my efforts to get the popular "DSP" POSIX libraries (sndfile, samplerate, fftw) working with scoop due to lack of time. I can always reopen this PR later if and when ready.

[tresf]

I can always reopen this PR later if and when ready.

Or equally, you can merge this and let developers relying on it provide feedback. :/

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[issaclin32]

The URL is not reachable. Need to fix later

[rashil2000]

Repo has moved to https://github.com/FFTW/fftw3 btw

[jasongodev]

@tresf what's the progress of this PR?

[tresf]

It's fine to close. The project it was aiming to help has moved away from scoop. There are likely other projects that will benefit from it, but automatically installing precompiled dependencies on Windows is still a ways off.