pkg/60246: math/fftw unnecessarily brings in gcc12

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>Number:         60246
>Category:       pkg
>Synopsis:       math/fftw unnecessarily brings in gcc12
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Sun May 10 09:55:01 +0000 2026
>Originator:     RVP
>Release:        pkgsrc-2026Q1
>Organization:
>Environment:
NetBSD/amd64 11.99.6
>Description:
Updating QEMU in 2026Q1 now brings in gcc12 as an indirect dependency.
This is ultimately due to FFTW now having a _run-time_ dependency on
gfortran:

https://github.com/NetBSD/pkgsrc/blob/trunk/math/fftw/options.mk#L5

and:

https://github.com/NetBSD/pkgsrc/blob/trunk/math/fftw/options.mk#L40

I don't see why it isn't just a build-time requirement to have a
FORTRAN compiler to get FFI right?

>How-To-Repeat:
Update to 2026Q1 and watch QEMU bringing in gcc12. Whoo-hoo!
>Fix:
pkgsrc magic reqd.