Update to FFTW 3.3.4

[tkelman]

Upstream update, looks pretty minor: https://github.com/FFTW/fftw3/blob/master/NEWS
2 of the 6 changes are solving problems on Windows that we had local Julia patches to fix, which we can now get rid of. Any reason not to do this now @stevengj ?

I can add checksum files if #6773 gets merged first.

[tkelman]

Whoops, my bad, I should've looked closer at 6193, this is entirely contained within that PR along with much more consequential changes. Probably no need to do this separately.

[stevengj]

Yes, I don't think there is any urgent reason to do this rather than waiting for #6193 to be finished in the 0.4 cycle.

[Keno]

@stevengj With recent clang, fftw failed to build for me with:

clang: error: unknown argument: '-malign-double' [-Wunused-command-line-argument-hard-error-in-future]

Was this fixed in 3.3.4?

[stevengj]

@loladiro, I don't think that was changed in 3.3.4, but I'm a little confused because the configure script checks whether malign-double gives an error before adding it to CFLAGS. If you look in the config.log file, there should be something like:

configure:13540: checking whether C compiler accepts -malign-double
configure:13559: gcc -c -malign-double  conftest.c >&5
configure:13559: $? = 0
configure:13569: result: yes

[Keno]

Oh, nevermind then. Maybe it had something to do with my build.

[ivarne]

I also experienced the -malgin-double problem and asked on julia-users. It is probably triggered by upgrading clang and then the makefile decides to rebuild fftw without running the configure script.

cofig.log shows

configure:13499: checking whether C compiler accepts -malign-double
configure:13518: clang -stdlib=libc++ -mmacosx-version-min=10.7 -c -malign-double  conftest.c >&5
clang: warning: argument unused during compilation: '-malign-double' 
configure:13518: $? = 0
configure:13528: result: yes

[stevengj]

@ivarne, can you try downloading the stock FFTW 3.3.4 on your machine to see whether it compiles?

[ivarne]

fftw-3.3.3 compiles if i delete the old build folder. I'll report back on 3.3.4 when I get a connection that does not give me big troubles with regular web browsing.